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Bhattacharya A, Khare SK. Ecological and toxicological manifestations of microplastics: current scenario, research gaps, and possible alleviation measures. J Environ Sci Health C Toxicol Carcinog 2020; 38:1-20. [PMID: 32397947 DOI: 10.1080/10590501.2019.1699379] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Microplastics (MPs) and associated contaminants have become a major environmental concern. From available literature, their ubiquitous presence is now well established. However, the kind and level of toxicological impacts these MPs accomplish on various life forms are not well understood. Nevertheless, the environmental toxicity of MP is now being revealed gradually with supporting studies involving groups of lower organisms. Additionally, the presence of microplastics also disturbs the functions of ecosystem through affecting the vulnerable life forms, thus ecological manifestations of MPs also need to be analyzed. The present review encompasses an overview of toxicological effects mediated by various types of MPs present in the environment; it covers the types of toxicity they may cause and other effects on humans and other species. In this review, aquatic systems are used as primary models to describe various eco-toxicological effects of MPs. Various research gaps as well as methods to alleviate the level of MPs, and future strategies are also comprehensively highlighted in the review.
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Affiliation(s)
- Amrik Bhattacharya
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Delhi, New Delhi, India
| | - S K Khare
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Delhi, New Delhi, India
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2
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Ghosh S, Ahmad R, Khare SK. Refolding of thermally denatured cholesterol oxidases by magnetic nanoparticles. Int J Biol Macromol 2019; 138:958-965. [PMID: 31325504 DOI: 10.1016/j.ijbiomac.2019.07.103] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 07/10/2019] [Accepted: 07/16/2019] [Indexed: 01/06/2023]
Abstract
Proteins are prone to unfolding and subsequent denaturation by changes in temperature, pH and other harsh conditions. Nanoparticles act as artificial 'chaperones' due to favourable orientation of the proteins on their scaffold which prevents aggregation and reconfigures denatured proteins into their native functional state. In the present study, thermal denaturation of Cholesterol oxidases from Pseudomonas aeruginosa PseA, Rhodococcus erythropolis MTCC 3951 and Streptomyces sp. were studied at temperatures 50-70 °C. Further, these thermally denatured proteins were refolded using functionalized Magnetic Iron (II, III) oxide nanoparticles which was confirmed using DLS, Zeta Potential Measurements, fluorescence and CD spectroscopy. The refolded proteins were found to regain their secondary structure and activity to a great extent.
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Affiliation(s)
- Shubhrima Ghosh
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India
| | - Razi Ahmad
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India
| | - S K Khare
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India.
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3
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Bhattacharya A, Naik SN, Khare SK. Efficacy of ureolytic Enterobacter cloacae EMB19 mediated calcite precipitation in remediation of Zn (II). J Environ Sci Health A Tox Hazard Subst Environ Eng 2019; 54:526-532. [PMID: 30729861 DOI: 10.1080/10934529.2019.1567184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 12/29/2018] [Accepted: 01/05/2019] [Indexed: 05/27/2023]
Abstract
In this study, urease mediated calcite precipitation technique was used for remediation of Zn (II). A urease positive Enterobacter cloacae EMB19 was used to produce calcite impregnated with Zn ions. In co-presence of Ca (II), Zn (II) concentrations of 10 and 20 mg L-1 were completely remediated by the bacterium from the media at 72 and 96 h of incubation, respectively. Co-precipitation of Ca (II) and Zn (II) to form calcite-Zn precipitate is one of the major mechanisms of Zn remediation in the present study. Role of urease in calcite-Zn precipitation was substantiated by using urease/carbonate and ammonium enriched cell free culture supernatant (CFS) obtained after sufficient microbial growth. Using CFS, 68% removal of initial 50 mg L-1 Zn (II) was detected. Energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction pattern (XRD) of the precipitate supports calcite mediated remediation of Zn. Remediation of multiple metals viz. Cd, Zn, Cu was also analyzed using CFS laden with urease. The preparation showed 40% Cd, 23% Zn, and 8% Cu reduction from the solution containing initial 25 mg L-1 of each metal. Overall, it can be concluded that, the E. cloacae mediated calcite precipitation technique could effectively be used for alleviation of Zn (II) and other heavy metals from the contaminated environment.
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Affiliation(s)
- Amrik Bhattacharya
- a Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry , Indian Institute of Technology, Delhi , New Delhi , India
- b Center for Rural Development and Technology, Indian Institute of Technology, Delhi , New Delhi , India
| | - S N Naik
- b Center for Rural Development and Technology, Indian Institute of Technology, Delhi , New Delhi , India
| | - S K Khare
- a Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry , Indian Institute of Technology, Delhi , New Delhi , India
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Ghosh S, Alam S, Rathore AS, Khare SK. Stability of Therapeutic Enzymes: Challenges and Recent Advances. Advances in Experimental Medicine and Biology 2019; 1148:131-150. [DOI: 10.1007/978-981-13-7709-9_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Chaturvedi S, Bhattacharya A, Khare SK. Trends in Oil Production from Oleaginous Yeast Using Biomass: Biotechnological Potential and Constraints. APPL BIOCHEM MICRO+ 2018. [DOI: 10.1134/s000368381804004x] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Bhattacharya A, Naik SN, Khare SK. Harnessing the bio-mineralization ability of urease producing Serratia marcescens and Enterobacter cloacae EMB19 for remediation of heavy metal cadmium (II). J Environ Manage 2018; 215:143-152. [PMID: 29567554 DOI: 10.1016/j.jenvman.2018.03.055] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 03/09/2018] [Accepted: 03/12/2018] [Indexed: 05/27/2023]
Abstract
In the present study, urease positive Serratia marcescens (NCIM2919) and Enterobacter cloacae EMB19 (MTCC10649) were individually evaluated for remediation of cadmium (II) using ureolysis-induced calcium carbonate precipitation. Both the cultures were observed to efficiently remove cadmium from the media through co-precipitation of Cd (II) and Ca (II). S. marcescens and E. cloacae EMB19, respectively showed 96 and 98% removal of initial 5.0 mg L-1 soluble Cd (II) from the urea and CaCl2 laden media at 96 h of incubation period. At higher Cd (II) concentrations of 10 and 15 mg L-1, cadmium removal efficiency was much higher in case of E. cloacae EMB19 compared to S. marcescens. In-vitro cadmium (II) remediation study using urease containing cell-free culture supernatant of S. marcescens and E. cloacae EMB19 showed respective 98 and 53% removal of initial 50 mg L-1 Cd (II) from the reaction mixtures in co-presence of Ca (II). While in sole presence of Cd (II), only 16 and 8% removal of Cd (II) were detected for S. marcescens and E. cloacae EMB19, respectively. The elemental analysis of the co-precipitated mineral products using Energy Dispersive X-ray spectroscopy (EDX) clearly showed the prevalence of Ca and Cd ions. The morphology Cd-Ca composites formed with respect to both the cultures were observed to be of different shape and size as revealed through Scanning Electron Microscopy (SEM). Entire study hence comes out with a sustainable bioremediation option which could be effectively used to tackle Cd (II) or other heavy metal pollution.
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Affiliation(s)
- Amrik Bhattacharya
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Delhi, New Delhi 11016, India; Center for Rural Development and Technology, Indian Institute of Technology, Delhi, New Delhi 110016, India
| | - S N Naik
- Center for Rural Development and Technology, Indian Institute of Technology, Delhi, New Delhi 110016, India
| | - S K Khare
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Delhi, New Delhi 11016, India.
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Grewal J, Khare SK. One-pot bioprocess for lactic acid production from lignocellulosic agro-wastes by using ionic liquid stable Lactobacillus brevis. Bioresour Technol 2018; 251:268-273. [PMID: 29288954 DOI: 10.1016/j.biortech.2017.12.056] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 12/17/2017] [Accepted: 12/18/2017] [Indexed: 06/07/2023]
Abstract
The lignocellulosic agro-wastes are an attractive renewable resource in biorefinery for production of value-added platform chemicals and biofuels. The study describes use of different agro-wastes as substrate for production of lactic acid, a C3-platform chemical and high demand industrial product by Lactobacillus brevis in a one-pot bioprocess. The simultaneous saccharification and co-fermentation (SSCF) process was achieved by L. brevis governed fermentation of sugars, derived from saccharification of ionic liquid pretreated feedstocks by nanoimmobilized cellulase, which was further recovered and used for consecutive cycle. The lactic acid yields of 0.22, 0.49, 0.52 g/g were obtained from cottonseed cake, wheat straw and sugarcane bagasse, respectively. The ionic liquid-tolerant L. brevis, cellulolytic reusable nanoimmobilized enzyme coupled with valorization of renewable feedstocks points towards a holistic approach for future biorefineries with sustainable production of bioproducts.
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Affiliation(s)
- Jasneet Grewal
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - S K Khare
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
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Sadaf A, Kumari A, Khare SK. Potential of ionic liquids for inhibiting the growth and β-lactamase production by Bacillus cereus EMB20. Int J Biol Macromol 2017; 107:1915-1921. [PMID: 29030198 DOI: 10.1016/j.ijbiomac.2017.10.053] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 10/06/2017] [Accepted: 10/09/2017] [Indexed: 12/21/2022]
Abstract
Present work reports the inhibition of Bacillus cereus EMB20 β-lactamase by a deep eutectic solvent, maline in an uncompetitive manner. Far-UV CD and intrinsic fluorescence spectroscopy revealed a disrupted secondary as well as tertiary structure as a function of maline concentration. The effect of individual components of maline on β-lactamase inhibition showed that malonic acid was mainly responsible for inhibiting the β-lactamase. Structural and docking studies found that malonic acid led to major perturbations in the secondary and tertiary structure of the enzyme while H-bonding with the active site residues. Further the antibacterial and cytotoxic studies also confirmed the potential of maline as a potent growth inhibitor of β-lactamase producing B. cereus EMB20.
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Affiliation(s)
- Ayesha Sadaf
- Department of Chemistry, Indian Institute of Technology, New Delhi, India
| | - Arti Kumari
- Department of Chemistry, Indian Institute of Technology, New Delhi, India
| | - S K Khare
- Department of Chemistry, Indian Institute of Technology, New Delhi, India.
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Grewal J, Ahmad R, Khare SK. Development of cellulase-nanoconjugates with enhanced ionic liquid and thermal stability for in situ lignocellulose saccharification. Bioresour Technol 2017; 242:236-243. [PMID: 28411048 DOI: 10.1016/j.biortech.2017.04.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/30/2017] [Accepted: 04/01/2017] [Indexed: 05/25/2023]
Abstract
The present work aimed to improve catalytic efficiency of Trichoderma reesei cellulase for enhanced saccharification. The cellulase was immobilized on two nanomatrices i.e. magnetic and silica nanoparticles with immobilization efficiency of 85% and 76% respectively. The nanobioconjugates exhibited increase in Vmax, temperature optimum, pH and thermal stability as compared with free enzyme. These could be efficiently reused for five repeated cycles and were stable in 1-ethyl-3-methylimidazoliumacetate [EMIM][Ac], an ionic liquid. Ionic liquids (IL) are used as green solvents to dissolve lignocellulosic biomass and facilitate better saccharification. The cellulase immobilized on magnetic nanoparticles was used for in situ saccharification of [EMIM][Ac] pretreated sugarcane bagasse and wheat straw for two cycles. The structural deconstruction and decrease in biomass crystallinity was confirmed by SEM, XRD and FTIR. The high hydrolysis yields (∼89%) obtained in this one-pot process coupled with IL stability and recycled use of immobilized cellulase, potentiates its usefulness in biorefineries.
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Affiliation(s)
- Jasneet Grewal
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Razi Ahmad
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - S K Khare
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
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Sadaf A, Sinha R, Khare SK. Structure and Functional Characterisation of a Distinctive β-Lactamase from an Environmental Strain EMB20 of Bacillus cereus. Appl Biochem Biotechnol 2017; 184:197-211. [PMID: 28664525 DOI: 10.1007/s12010-017-2539-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 06/14/2017] [Indexed: 11/30/2022]
Abstract
The rampant use and misuse of antibiotics in human medicine, agriculture and veterinary have become the key contributors to global antimicrobial resistance. One of the significant resistance mechanisms that inactivates antibiotics and impedes treatment of bacterial infections is the expression of β-lactamases. Rising evidence of newer variants of β-lactamases in the environment is therefore a serious threat to the presently available antibiotic armoury. The present work describes the purification of a variant β-lactamase isolated from a soil strain EMB20 of Bacillus cereus. The lactamase was purified using three-phase partitioning and gel filtration chromatography to a 30-fold purification and 15% recovery yield. Contrary to the general trend, the lactamase was not a metalloenzyme, but its activity was enhanced in the presence of Mg2+ and Mn2+. The EMB20 lactamase exhibited improved stability against inhibitors and denaturing agents such as urea and GdmCl as compared to its commercial analogue. The improved stability of EMB20 lactamase was further validated by circular dichroism and fluorescence spectroscopy. This study reemphasizes the rising prevalence of environmental lactamase variants. Decoding the structure-function correlation of such lactamases in the presence of inhibitors will provide insights into the response of this enzyme towards inhibitors as well as its substrates.
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Affiliation(s)
- Ayesha Sadaf
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi, 110016, India
| | - Rajeshwari Sinha
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi, 110016, India
| | - S K Khare
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi, 110016, India.
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Sadaf A, Khare SK. Efficacy of ionic liquids on the growth and simultaneous xylanase production by Sporotrichum thermophile: membrane integrity, composition and morphological investigation. RSC Adv 2017. [DOI: 10.1039/c6ra27979a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Ionic liquids (ILs) are emerging as promising solvent systems for carrying out various biochemical reactions.
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Affiliation(s)
- Ayesha Sadaf
- Enzyme and Microbial Biochemistry Laboratory
- Department of Chemistry
- Indian Institute of Technology
- New Delhi 110016
- India
| | - S. K. Khare
- Enzyme and Microbial Biochemistry Laboratory
- Department of Chemistry
- Indian Institute of Technology
- New Delhi 110016
- India
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Ghosh S, Khare SK. Biodegradation of cytotoxic 7-Ketocholesterol by Pseudomonas aeruginosa PseA. Bioresour Technol 2016; 213:44-49. [PMID: 27020128 DOI: 10.1016/j.biortech.2016.03.079] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 03/11/2016] [Accepted: 03/12/2016] [Indexed: 06/05/2023]
Abstract
The present study aims to degrade 7-Ketocholesterol (7KC), a major oxysterol implicated in many age-related disorders, through microbial means and find candidate enzymes involved for further application in food systems and as a therapeutic. During initial screening of previously isolated bacteria from our laboratory, Pseudomonas aeruginosa PseA was found to be a potential degrader strain using 7KC as a sole carbon source. Under optimized conditions, it is able to degrade 88% of an initial concentration of 1000ppm (1g/l) 7KC. Preliminary in vitro studies with extra-cellular extract has shown degradation of the compound, thus reinforcing the occurrence of suitable enzymatic systems involved in the process. We have been able to identify cholesterol oxidase as one such potential enzyme. Some intermediate products of degradation have also been identified. This is the first detailed report of 7KC degradation by a P. aeruginosa strain.
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Affiliation(s)
- Shubhrima Ghosh
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - S K Khare
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
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Sinha R, Khare SK. Immobilization of halophilic Bacillus sp. EMB9 protease on functionalized silica nanoparticles and application in whey protein hydrolysis. Bioprocess Biosyst Eng 2014; 38:739-48. [DOI: 10.1007/s00449-014-1314-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 10/18/2014] [Indexed: 01/26/2023]
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Sinha R, Khare SK. Effect of organic solvents on the structure and activity of moderately halophilic Bacillus sp. EMB9 protease. Extremophiles 2014; 18:1057-66. [PMID: 25134948 DOI: 10.1007/s00792-014-0683-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 07/24/2014] [Indexed: 11/29/2022]
Abstract
Halophilic enzymes have been manifested for their stability and catalytic abilities under harsh operational conditions. These have been documented to withstand denaturation in presence of high temperature, pH, presence of organic solvents and chaotropic agents. The present study aims at understanding the stability and activity of a halophilic Bacillus sp. EMB9 protease in organic solvents. The protease was uniquely stable in polar solvents. A clear correlation was evident between the protease function and conformational transitions, validated by CD and fluorescence spectral studies. The study affirms that preservation of protein structure, possibly due to charge screening of the protein surface by Ca(2+) and Na(+) ions provides stability against organic solvents and averts denaturation. Salt was also found to exert a protective effect on dialyzed protease against chaotropism of solvents. Presence of 1 % (w/v) NaCl restored the activity in the dialyzed protease and prevented denaturation in methanol, toluene and n-decane. The work will have further implication on discerning protein folding in saline as well as non-aqueous environments.
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Affiliation(s)
- Rajeshwari Sinha
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi, 110016, India
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Sinha R, Srivastava AK, Khare SK. EFFICIENT PROTEOLYSIS AND APPLICATION OF AN ALKALINE PROTEASE FROM HALOPHILICBacillussp. EMB9. Prep Biochem Biotechnol 2014; 44:680-96. [DOI: 10.1080/10826068.2013.844711] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Sadaf A, Khare SK. Production of Sporotrichum thermophile xylanase by solid state fermentation utilizing deoiled Jatropha curcas seed cake and its application in xylooligosachharide synthesis. Bioresour Technol 2014; 153:126-130. [PMID: 24362246 DOI: 10.1016/j.biortech.2013.11.058] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 11/19/2013] [Accepted: 11/21/2013] [Indexed: 06/03/2023]
Abstract
De-oiled Jatropha curcas seed cake, a plentiful by-product of biodiesel industry was used as substrate for the production of a useful xylanase from Sporotrichum thermophile in solid state fermentation. Under the optimized conditions, 1025U xylanase/g (deoiled seed cake) was produced. The xylanase exhibited half life of 4h at 45°C and 71.44min at 50°C respectively. It was stable in a broad pH range of 7.0-11.0. Km and Vmax were 12.54mg/ml and 454.5U/ml/min respectively. S. thermophile xylanase is an endoxylanase free of exoxylanase activity, hence advantageous for xylan hydrolysis to produce xylooligosachharides. Hydrolysis of oat spelt xylan by S. thermophile xylanase yielded 73% xylotetraose, 15.4% xylotriose and 10% xylobiose. The S. thermophile endoxylanase thus seem potentially useful in the food industries.
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Affiliation(s)
- Ayesha Sadaf
- Department of Chemistry, Indian Institute of Technology, New Delhi 110016, India
| | - S K Khare
- Department of Chemistry, Indian Institute of Technology, New Delhi 110016, India.
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Sinha R, Khare SK. Characterization of detergent compatible protease of a halophilic Bacillus sp. EMB9: differential role of metal ions in stability and activity. Bioresour Technol 2013; 145:357-361. [PMID: 23219691 DOI: 10.1016/j.biortech.2012.11.024] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 11/02/2012] [Accepted: 11/03/2012] [Indexed: 06/01/2023]
Abstract
A moderately halophilic protease producer, Bacillus sp. strain isolated from sea water is described. The protease is purified to homogeneity by ammonium sulphate precipitation and CM cellulose chromatography. The serine protease has a molecular mass of 29 kDa. Enzymatic characterization of protease revealed K(m) 2.22 mg mL(-1), Vmax 1111.11 U mL(-1), pH optimum 9.0, t1/2 190 min at 60°C and salt optima 1% (w/v) NaCl. The protease is remarkably stable in hydrophilic and hydrophobic solvents at high concentrations. The purified preparation is unstable at room temperature. Ca(2+) ions are required for preventing this loss of activity. Interestingly, the activity and stability are modulated differentially. Whereas, divalent cation Ca(2+) are involved in maintaining stability in solution at room temperature by preventing unfolding, monovalent Na(+) and K(+) ions participate in regulating the activity and assist in refolding of the enzyme. Application of the protease is shown in efficient removal of blood stain.
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Affiliation(s)
- Rajeshwari Sinha
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Delhi, New Delhi, India
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20
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Kumar S, Khare SK. Purification and characterization of maltooligosaccharide-forming α-amylase from moderately halophilic Marinobacter sp. EMB8. Bioresour Technol 2012; 116:247-251. [PMID: 22197336 DOI: 10.1016/j.biortech.2011.11.109] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2011] [Revised: 11/21/2011] [Accepted: 11/25/2011] [Indexed: 05/26/2023]
Abstract
Maltooligosaccharides especially maltotriose and maltotetraose producing amylases are highly desirable for application in bread making and other food industries. A maltotriose and maltotetraose producing amylase from moderately halophilic Marinobacter sp. EMB8 is described. Under optimized culture conditions, 48.0 IU/mL amylase was obtained. The enzyme was purified to homogeneity by ultrafiltration, DEAE cellulose and Sephadex G-75 column chromatography with 52% yield and 76-fold purification. It was a monomeric protein of 72 kDa. The amylase had many novel features viz. stability up to 20% NaCl, 80 °C temperature, pH 6.0-11.0 and in wide range of organic solvents at high concentrations. The enzyme efficiently hydrolyzed starch into maltooligosaccharides rich in maltotriose and maltotetraose. These novel properties make the Marinobacter sp. amylase a potentially useful enzyme.
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Affiliation(s)
- Sumit Kumar
- Department of Chemistry, Indian Institute of Technology, Delhi, New Delhi, India
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Abstract
A novel protease from the halophilic bacterium Geomicrobium sp. EMB2 (MTCC 10310) is described. The activity of the protease was modulated by salt, and it exhibited remarkable stability in organic solvents, at alkaline pH, and in other denaturing conditions. The structural changes under various denaturing conditions were analyzed by measurements of intrinsic fluorescence and circular dichroism spectroscopy. Circular dichroism showed that the secondary structure of the protease was predominantly α-helical but unfolded in salt-free medium. The structure is regained by inclusion of NaCl in the range of 2-5%. The presence of NaCl exerted a protective effect against thermal, organic solvent, and guanidine hydrochloride denaturation by preventing unfolding.
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Affiliation(s)
- R Karan
- Department of Chemistry, Indian Institute of Technology, Delhi, New Delhi, India
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Joshi C, Mathur P, Khare SK. Degradation of phorbol esters by Pseudomonas aeruginosa PseA during solid-state fermentation of deoiled Jatropha curcas seed cake. Bioresour Technol 2011; 102:4815-4819. [PMID: 21316957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 01/13/2011] [Accepted: 01/14/2011] [Indexed: 05/30/2023]
Abstract
Large amount of seed cake is generated as by-product during biodiesel production from Jatropha seeds. Presence of toxic phorbol esters restricts its utilization as livestock feed. Safe disposal or meaningful utilization of this major by-product necessitates the degradation of these phorbol esters. The present study describes the complete degradation of phorbol esters by Pseudomonas aeruginosa PseA strain during solid state fermentation (SSF) of deoiled Jatropha curcas seed cake. Phorbol esters were completely degraded in nine days under the optimized SSF conditions viz. deoiled cake 5.0 g; moistened with 5.0 ml distilled water; inoculum 1.5 ml of overnight grown P. aeruginosa; incubation at temperature 30 °C, pH 7.0 and RH 65%. SSF of deoiled cake seems a potentially viable approach towards the complete degradation of the toxic phorbol esters.
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Affiliation(s)
- Chetna Joshi
- Enzyme and Microbial Biochemistry Lab, Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India
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24
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Joshi C, Khare SK. Utilization of deoiled Jatropha curcas seed cake for production of xylanase from thermophilic Scytalidium thermophilum. Bioresour Technol 2011; 102:1722-1726. [PMID: 20855195 DOI: 10.1016/j.biortech.2010.08.070] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 08/17/2010] [Accepted: 08/19/2010] [Indexed: 05/29/2023]
Abstract
Jatropha curcas is a major biodiesel crop. Large amount of deoiled cake is generated as by-product during biodiesel production from its seeds. Deoiled J. curcas seed cake was assessed as substrate for the production of xylanase from thermophilic fungus Scytalidium thermophilum by solid-state fermentation. The seed cake was efficiently utilized by S. thermophilum for its growth during which it produced good amount of heat stable extracellular xylanase. The solid-state fermentation conditions were optimized for maximum xylanase production. Under the optimized conditions viz. deoiled seed cake supplemented with 1% oat-spelt xylan, adjusted to pH 9.0, moisture content 1:3 w/v, inoculated with 1×10(6) spores per 5 g cake and incubated at 45 °C, 1455 U xylanase/g deoiled seed cake was obtained. The xylanase was useful in biobleaching of paper pulp. Solid-state fermentation of deoiled cake appears a potentially viable approach for its effective utilization.
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Affiliation(s)
- Chetna Joshi
- Enzyme and Microbial Biochemistry Lab, Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi 110 016, India
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25
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Sinha R, Karan R, Sinha A, Khare SK. Interaction and nanotoxic effect of ZnO and Ag nanoparticles on mesophilic and halophilic bacterial cells. Bioresour Technol 2011; 102:1516-20. [PMID: 20797851 DOI: 10.1016/j.biortech.2010.07.117] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Revised: 07/29/2010] [Accepted: 07/30/2010] [Indexed: 05/07/2023]
Abstract
The toxicity of two commonly used nanoparticles, silver and zinc oxide on mesophilic and halophilic bacterial cells has been investigated. Enterobacter sp., Marinobacter sp., Bacillus subtilis, halophilic bacterium sp. EMB4, were taken as model systems. The nanotoxicity was more pronounced on Gram negative bacteria. ZnO nanoparticles reduced the growth of Enterobacter sp. by 50%, while 80% reduction was observed in halophilic Marinobacter sp. In case of halophiles, this may be attributed to higher content of negatively charged cardiolipins on their cell surface. Interestingly, bulk ZnO exerted minimal reduction in growth. Ag nanoparticles were similarly cytotoxic. Nanotoxicity towards Gram positive cells was significantly less, possibly due to presence of thicker peptidoglycan layer. The bacterium nanoparticle interactions were probed by electron microscopy and energy dispersive X-ray analysis. The results indicated electrostatic interactions between nanoparticles and cell surface as the primary step towards nanotoxicity, followed by cell morphological changes, increase in membrane permeability and their accumulation in the cytoplasm.
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Affiliation(s)
- Rajeshwari Sinha
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Delhi, New Delhi, India
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26
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Abstract
A moderately haloalkaliphilic bacterium, Geomicrobium sp. EMB2, was isolated from the Sambhar Salt Lake located in the western part of India. It secreted an alkaline protease, which was stable and active in the presence of a wide range of organic solvents. The protease was purified by hydrophobic interaction chromatography on Phenyl Sepharose 6 Fast Flow matrix, and a 22.6-fold purification with 51.2% recovery was attained. The apparent molecular mass was estimated to be 38 kDa. The enzyme was stable in the pH range 6.0-12.0, the optimum being 10.0. The Km and Vmax towards casein were found to be 0.10 mM and 526 U/min, respectively. The protease was most active at 50 degrees C. It appeared to be serine type, owing to its sensitivity to phenylmethylsulphonyl fluoride (PMSF). It withstood a range of detergents and surfactants, and exhibited remarkable stability in the presence of solvents having a log P >2. The presence of NaCl or osmolytes exerted a protective effect and further enhanced the stability of the enzyme. These properties make this novel protease potentially useful for catalysis in non-aqueous medium.
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Affiliation(s)
- Ram Karan
- Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology - Delhi, Hauz Khas, New Delhi 110016, India
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27
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Abstract
Solvent-tolerant microbes are a newly emerging class that possesses the unique ability to thrive in the presence of organic solvents. Their enzymes adapted to mediate cellular and metabolic processes in a solvent-rich environment and are logically stable in the presence of organic solvents. Enzyme catalysis in non-aqueous/low-water media is finding increasing applications for the synthesis of industrially important products, namely peptides, esters, and other trans-esterification products. Solvent stability, however, remains a prerequisite for employing enzymes in non-aqueous systems. Enzymes, in general, get inactivated or give very low rates of reaction in non-aqueous media. Thus, early efforts, and even some recent ones, have aimed at stabilization of enzymes in organic media by immobilization, surface modifications, mutagenesis, and protein engineering. Enzymes from solvent-tolerant microbes appear to be the choicest source for studying solvent-stable enzymes because of their unique ability to survive in the presence of a range of organic solvents. These bacteria circumvent the solvent's toxic effects by virtue of various adaptations, e.g. at the level of the cytoplasmic membrane, by degradation and transformation of solvents, and by active excretion of solvents. The recent screening of these exotic microbes has generated some naturally solvent-stable proteases, lipases, cholesterol oxidase, cholesterol esterase, cyclodextrin glucanotransferase, and other important enzymes. The unique properties of these novel biocatalysts have great potential for applications in non-aqueous enzymology for a range of industrial processes.
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Affiliation(s)
- Anshu Gupta
- School of Environment Management, Guru Gobind Singh Indraprastha University, Kashmere Gate, Delhi, India
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28
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Gaur R, Gupta GN, Vamsikrishnan M, Khare SK. Protein-Coated Microcrystals of Pseudomonas aeruginosa PseA lipase. Appl Biochem Biotechnol 2008; 151:160-6. [DOI: 10.1007/s12010-008-8163-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2007] [Accepted: 01/28/2008] [Indexed: 10/21/2022]
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29
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Ruchi G, Anshu G, Khare SK. Lipase from solvent tolerant Pseudomonas aeruginosa strain: production optimization by response surface methodology and application. Bioresour Technol 2008; 99:4796-4802. [PMID: 17976982 DOI: 10.1016/j.biortech.2007.09.053] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Revised: 09/18/2007] [Accepted: 09/20/2007] [Indexed: 05/25/2023]
Abstract
Solvent tolerant Pseudomonas aeruginosa strain PseA has been studied for lipase activity. This strain has earlier been reported to be secreting alkaline and solvent stable protease. It produced an extra cellular lipase with suitable properties for detergent applications viz. (i) alkaline in nature, (ii) stability and compatibility towards bleach oxidants, surfactants and detergent formulations and (iii) resistant to proteolysis. Since the culture supernatant contains both protease and lipase which are together required in detergent formulations, enzymes from P. aeruginosa seem ideal for use as detergent additive. P. aeruginosa lipase exhibited remarkable stability in wide range of organic solvents at 25% (v/v) concentration. This property can be useful for solvent bioremediation and biotransformations in non-aqueous media. Media optimization for cost effective production of lipase was carried out by response surface methodology which led to 5.58-fold increase in lipase production (4580 IU/ml) over un-optimized media.
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Affiliation(s)
- Gaur Ruchi
- Chemistry Department, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016, India
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30
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Mahanta N, Gupta A, Khare SK. Production of protease and lipase by solvent tolerant Pseudomonas aeruginosa PseA in solid-state fermentation using Jatropha curcas seed cake as substrate. Bioresour Technol 2008; 99:1729-35. [PMID: 17509877 DOI: 10.1016/j.biortech.2007.03.046] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2007] [Revised: 03/29/2007] [Accepted: 03/29/2007] [Indexed: 05/15/2023]
Abstract
Deoiled Jatropha seed cake was assessed for its suitability as substrate for enzyme production by solid-state fermentation (SSF). Solvent tolerant Pseudomonas aeruginosa PseA strain previously reported by us was used for fermentation. The seed cake supported good bacterial growth and enzyme production (protease, 1818 U/g of substrate and lipase, 625 U/g of substrate) as evident by its chemical composition. Maximum protease and lipase production was observed at 50% substrate moisture, a growth period of 72 and 120 h, and a substrate pH of 6.0 and 7.0, respectively. Enrichment with maltose as carbon source increased protease and lipase production by 6.3- and 1.6-fold, respectively. Nitrogen supplementation with peptone for protease and NaNO(3) for lipase production also enhanced the enzyme yield reaching 11,376 U protease activity and 1084 U lipase activity per gram of Jatropha seed cake. These results demonstrated viable approach for utilization of this huge biomass by solid-state fermentation for the production of industrial enzymes. This offers significant benefit due to low cost and abundant availability of cake during biodiesel production.
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Affiliation(s)
- Nilkamal Mahanta
- Chemistry Department, Indian Institute of Technology, Delhi, Hauz-Khas, New Delhi, India
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31
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Dodia MS, Rawal CM, Bhimani HG, Joshi RH, Khare SK, Singh SP. Purification and stability characteristics of an alkaline serine protease from a newly isolated Haloalkaliphilic bacterium sp. AH-6. J Ind Microbiol Biotechnol 2007; 35:121-31. [DOI: 10.1007/s10295-007-0273-x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Accepted: 10/20/2007] [Indexed: 10/22/2022]
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32
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Gupta A, Ray S, Kapoor S, Khare SK. Solvent-stable Pseudomonas aeruginosa PseA protease gene: identification, molecular characterization, phylogenetic and bioinformatic analysis to study reasons for solvent stability. J Mol Microbiol Biotechnol 2007; 15:234-43. [PMID: 17715461 DOI: 10.1159/000107488] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We have previously isolated a solvent-stable protease from a novel solvent-tolerant strain of Pseudomonas aeruginosa (PseA). Here we report cloning and characterization of the gene coding for this solvent-tolerant protease. A homology search of the N-terminal amino acid sequence of the purified PseA protease revealed an exact match to a P. aeruginosa PST-01 protease gene, lasB. The c-DNA sequence of the PST-01 protease was used to design primers for the amplification of a 1,494-bp open reading frame encoding a 53.6-kDa, 498-amino-acid PseA LasB polypeptide. The deduced PseA LasB protein contained a 23-residue signal peptide (2.6 kDa) followed by a propeptide of 174 residues and a 33-kDa mature product of 301 residues. A phylogenetic analysis placed PseA lasB closest to the known zinc metalloproteases from P. aeruginosa. This gene was also found to contain a conserved HEXXH zinc-binding motif, characteristic of all zinc metallopeptidases. The 3D structure analysis of PseA protease revealed the presence of 7 alpha-helices (36% of the sequence). The molecule was found to have two disulfide bonds (between Cys-227 and Cys-255 and between Cys-467 and Cys-494) and had a number of hydrophobic clusters at the protein surface. These hydrophobic patches (21% of the sequence) and disulfide bonds may possibly be responsible for the solvent-stable nature of the enzyme.
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Affiliation(s)
- Anshu Gupta
- Chemistry Department, Indian Institute of Technology, New Delhi, India
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33
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Gaur R, Sharma A, Khare SK, Gupta MN. A novel process for extraction of edible oils: Enzyme assisted three phase partitioning (EATPP). Bioresour Technol 2007; 98:696-9. [PMID: 16574406 DOI: 10.1016/j.biortech.2006.01.023] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2004] [Revised: 01/09/2006] [Accepted: 01/31/2006] [Indexed: 05/08/2023]
Abstract
Three phase partitioning (TPP), a technique used in protein purification has been evaluated, for extraction of oil from three different plant sources viz: mango kernel, soybean and rice bran. The process consists of simultaneous addition of t-butanol (1:1,v/v) and ammonium sulphate (w/v) to a crude preparation/slurry. Under optimized condition, the protein appears as an interfacial precipitate between upper t-butanol containing oil and lower aqueous phase. Pretreatment of the slurries with a commercial enzyme preparation of proteases, Protizyme, followed by three phase partitioning resulted in 98%, 86% and 79% (w/w) oil yields in case of soybean, rice bran and mango kernel, respectively. The efficiency of the present technique is comparable to solvent extraction with an added advantage of being less time consuming and using t-butanol which is a safer solvent as compared to n-hexane used in conventional oil extraction process.
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Affiliation(s)
- Ruchi Gaur
- Chemistry Department, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016, India
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34
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Gupta A, Khare SK. A protease stable in organic solvents from solvent tolerant strain of Pseudomonas aeruginosa. Bioresour Technol 2006; 97:1788-93. [PMID: 16242320 DOI: 10.1016/j.biortech.2005.09.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2005] [Revised: 09/03/2005] [Accepted: 09/05/2005] [Indexed: 05/05/2023]
Abstract
A solvent tolerant strain of Pseudomonas aeruginosa (PseA) was isolated from soil samples by cyclohexane enrichment in medium. The strain was able to sustain and grow in a wide range of organic solvents. The adaptation of P. aeruginosa cell towards solvents was seen at membrane level in transmission electron micrographs. It also secreted a novel protease, which exhibited remarkable solvent stability and retained most of the activity at least up to 10 days in the presence of hydrophobic organic solvents (log P > or = 2.0) at 25% (v/v) concentrations. The protease was able to withstand as high as 75% concentration of solvents at least up to 48 h. P. aeruginosa strain and its protease, both seem promising for solvent bioremediation, wastewater treatment and carrying out biotransformation in non-aqueous medium.
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Affiliation(s)
- Anshu Gupta
- Department of Chemistry, Indian Institute of Technology, Delhi, Hauz-Khas, New Delhi
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35
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Gupta A, Singh R, Khare SK, Gupta MN. A solvent tolerant isolate of Enterobacter aerogenes. Bioresour Technol 2006; 97:99-103. [PMID: 16154507 DOI: 10.1016/j.biortech.2005.02.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2004] [Revised: 02/08/2005] [Accepted: 02/10/2005] [Indexed: 05/04/2023]
Abstract
A solvent tolerant strain of Enterobacter aerogenes was isolated from soil by cyclohexane enrichment. Presence of cyclohexane (20%) in culture media prolonged the lag phase and caused reduction in biomass. Transmission electron micrographs showed convoluted cell membrane and accumulation of solvent in case of the cells grown in cyclohexane. The Enterobacter isolate was able to grow in the range of organic solvents having log P above 3.2 and also in presence of mercury, thus showing potential for treatment of solvent rich wastes.
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Affiliation(s)
- Anshu Gupta
- Department of Chemistry, Indian Institute of Technology, Delhi, Hauz-Khas, New Delhi-110 016, India
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36
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Abstract
A solvent tolerant Pseudomonas aeruginosa PseA strain was isolated from soil. It secreted a novel alkaline protease, which was stable and active in the presence of range of organic solvents, thus potentially useful for catalysis in non-aqueous media. The protease was purified 11.6-fold with 60% recovery by combination of ion exchange and hydrophobic interaction chromatography using Q-Sepharose and Phenyl Sepharose 6 Fast Flow matrix, respectively. The apparent molecular mass based on the sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) was estimated to be 35,000 Da. The enzyme was stable in the pH range of 6.0-9.0, the optimum being 8.0. The Km and Vmax towards caseinolytic activity were found to be 2.7 mg/ml and 3 micromol/min, respectively. The protease was most active at 60 degrees C and characterized as a metalloprotease because of its sensitivity to EDTA and 1,10-phenanthroline. It was tested positive for elastase activity towards elastin-orcein, thus appears to be an elastase, which is known as pseudolysin in other strains of P. aeruginosa. The protease withstands range of detergents, surfactants and solvents. It is stable and active in all the solvents having log P above 3.2, at least up to 72 h. These two properties make it an ideal choice for applications in detergent formulations and enzymatic peptide synthesis.
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Affiliation(s)
- Anshu Gupta
- Chemistry Department, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India
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37
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Gupta A, Roy I, Patel RK, Singh SP, Khare SK, Gupta MN. One-step purification and characterization of an alkaline protease from haloalkaliphilic Bacillus sp. J Chromatogr A 2005; 1075:103-8. [PMID: 15974123 DOI: 10.1016/j.chroma.2005.03.127] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
An alkaline protease producer haloalkaliphilic bacteria (isolate Vel) was isolated from west coast of India. It was related to Bacillus pseudofirmus on the basis of 16S r RNA gene sequencing, lipid profile and other biochemical properties. The protease secreted by this bacteria was purified 10-fold with 82% yield by a single step method on Phenyl Sepharose 6 Fast Flow column. The apparent molecular mass based on the sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) was estimated to be 29 000 Da. The Km and Vmax towards caseinolytic activity were found to be 2 mg ml(-1) and 289.8 microg min(-1), respectively. The enzyme was active over the pH range of 8.5-12.0, the optimum being 10-11.0. The purified enzyme when kept at 45 degrees C and 50 degrees C for 40 min retained 92% and 85% protease activity, respectively. Effect of NaCl concentration on protease activity showed that the enzyme was slightly inhibited with high concentration of salt. The proteolytic activity was inhibited by PMSF, suggesting that the enzyme may belong to serine type protease. Interestingly, the activity was slightly enhanced with SDS (0.1%) and Triton X-100 (0.1%) but remained unaffected by Tween 80 (0.1%). The activity was affected by metal ions to varying extent. While Mn2+, Zn2+ and Mg2+ had no significant effect on protease activity, the enzyme was activated with Ca2+ (1 mM) and Cu2+ (5 mM). The stability of the enzyme in the presence of detergent components and surfactants is particularly attractive for its application in detergent industries.
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Affiliation(s)
- Anshu Gupta
- Chemistry Department, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India
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38
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Roy I, Gupta A, Khare SK, Bisaria VS, Gupta MN. Immobilization of xylan-degrading enzymes from Melanocarpus albomyces IIS 68 on the smart polymer Eudragit L-100. Appl Microbiol Biotechnol 2003; 61:309-13. [PMID: 12743759 DOI: 10.1007/s00253-002-1213-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2002] [Revised: 11/29/2002] [Accepted: 11/29/2002] [Indexed: 12/18/2022]
Abstract
Xylanase of Melanocarpus albomyces IIS 68 was immobilized on Eudragit L-100. The latter is a copolymer of methacrylic acid and methyl methacrylate and is a pH-sensitive smart polymer. The immobilization was carried out by gentle adsorption and an immobilization efficiency of 0.82 was obtained. The enzyme did not leach off the polymer even in the presence of 1 M NaCl and 50% ethylene glycol. The K(m) of the enzyme changed from 5.9 mg ml(-1) to 9.1 mg ml(-1) upon immobilization. The V(max) of the immobilized enzyme showed an increase from 90.9 micro mol ml(-1) min(-1) (for the free enzyme) to 111.1 micro mol ml(-1) min(-1). The immobilized enzyme could be reused up to ten times without impairment of the xylanolytic activity. The immobilized enzyme was also evaluated for its application in pre-bleaching of eucalyptus kraft pulp.
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Affiliation(s)
- I Roy
- Department of Chemistry, Indian Institute of Technology, Delhi, Hauz Khas, 110016 New Delhi, India
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39
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Abstract
Three phase partitioning, a method generally used for protein separation, has been evaluated for extraction of oil from soybean. 82% oil was extracted within 1 h using this process which required simultaneous addition of t-butanol (1:1, v/v) and 30% ammonium sulphate to the soybean slurry.
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Affiliation(s)
- Aparna Sharma
- Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi
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40
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Affiliation(s)
- Aparna Sharma
- ; Chemistry Department; Indian Institute of Technology; Hauz Khas 110 016 New Delhi India
| | - S. K. Khare
- ; Chemistry Department; Indian Institute of Technology; Hauz Khas 110 016 New Delhi India
| | - M. N. Gupta
- ; Chemistry Department; Indian Institute of Technology; Hauz Khas 110 016 New Delhi India
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41
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Abstract
It was found that alginate binds to glucoamylase, presumably through the recognition of starch binding domain of the latter. The present work exploits this for purification of glucoamylases from commercial preparation of Aspergillus niger and crude culture filtrate of Bacillus amyloliquefaciens by affinity precipitation technique in a single-step protocol. Glucoamylase is selectively precipitated using alginate as macroaffinity ligand and later eluted with 1.0 M maltose. In the case of A. niger, 81% activity is recovered with 28-fold purification. The purified glucoamylase gave a single band on SDS-PAGE corresponding to 78 kDa molecular weight. The developed affinity precipitation process also works efficiently for purification of Bacillus amyloliquefaciens glucoamylase from its crude culture filtrate, giving 78% recovery with 38-fold purification. The purified preparation showed a major band corresponding to 62 kDa and a faint band about 50 kDa on SDS-PAGE. The latter corresponds to the molecular weight for alpha-amylase of Bacillus amyloliquefaciens.
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Affiliation(s)
- S Teotia
- Chemistry Department, Indian Institute of Technology, Hauz Khas, New Delhi-110016, India
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42
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Affiliation(s)
- Aparna Sharma
- ; Chemistry Department; Indian Institute of Technology; Hauz Khas 110016 New Delhi India
| | - S. K. Khare
- ; Chemistry Department; Indian Institute of Technology; Hauz Khas 110016 New Delhi India
| | - M. N. Gupta
- ; Chemistry Department; Indian Institute of Technology; Hauz Khas 110016 New Delhi India
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43
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Singh R, Nath A, Gupta PP, Shukla M, Khare SK, Kundu B. Antiallergic/antiasthmatic effect of novel antiallergic hexapeptide-95/220 in various experimental models. Indian J Exp Biol 2001; 39:871-7. [PMID: 11831367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
The effects of newly synthesized antiallergic hexapeptide 95/220 was investigated on various allergic and asthmatic test models. This newly developed peptide was found to be more potent than clinically used drug disodium cromoglycate (DSCG). Hexapeptide 95/220 inhibited immediate hypersensitivity reactions such as passive cutaneous anaphylaxis (PCA) and mast cell degranulation in rats, antigen-induced bronchoconstriction in actively sensitized guinea pigs in dose dependent manner like DSCG. Antigen-induced contraction of guinea pig ileum was also markedly inhibited by this newly developed hexapeptide in the same fashion as ketotifen and DSCG did but at comparatively lower dose. Egg albumin-induced histamine release was also blocked by this hexapeptide from chopped lung tissues of sensitized guinea pigs. These results suggest that hexapeptide' 95/220 has potent inhibitory effect on immediate hypersensitivity reactions thereby inhibiting mediator release from mast cell. Moreover, this newly synthesized peptide is orally active and effective at lower doses as compared to standard drugs.
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Affiliation(s)
- R Singh
- Division of Pharmacology, Central Drug Research Institute, Lucknow, India
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44
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Abstract
A. niger cellulase was crosslinked by glutaraldehyde to obtain a heat-stable enzyme preparation for rice hull cellulose hydrolysis. Under optimized crosslinking conditions of 0.12 M glutaraldehyde, pH 7.0, temperature 40 degrees C and at 45 min of crosslinking, a preparation having 15% more activity than free enzyme was obtained which also had considerable improvement in heat stability at 65 degrees C and 70 degrees C. Whereas the free enzyme lost 80% of its activity in 4 h at 65 degrees C, the crosslinked preparation lost only 30% activity. The crosslinked preparation hydrolyzed cellulosic biomass more effectively giving 2.2 mg/ml glucose and 52% corresponding saccharification in 4 h at 65 degrees C as compared to 14% saccharification by free enzyme under similar conditions.
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Affiliation(s)
- A Sharma
- Chemistry Department, Indian Institute of Technology, New Delhi
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45
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Banin E, Khare SK, Naider F, Rosenberg E. Proline-rich peptide from the coral pathogen Vibrio shiloi that inhibits photosynthesis of Zooxanthellae. Appl Environ Microbiol 2001; 67:1536-41. [PMID: 11282602 PMCID: PMC92766 DOI: 10.1128/aem.67.4.1536-1541.2001] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The coral-bleaching bacterium Vibrio shiloi biosynthesizes and secretes an extracellular peptide, referred to as toxin P, which inhibits photosynthesis of coral symbiotic algae (zooxanthellae). Toxin P was produced during the stationary phase when the bacterium was grown on peptone or Casamino Acids media at 29 degrees C. Glycerol inhibited the production of toxin P. Toxin P was purified to homogeneity, yielding the following 12-residue peptide: PYPVYAPPPVVP (molecular weight, 1,295.54). The structure of toxin P was confirmed by chemical synthesis. In the presence of 12.5 mM NH(4)Cl, pure natural or synthetic toxin P (10 microM) caused a 64% decrease in the photosynthetic quantum yield of zooxanthellae within 5 min. The inhibition was proportional to the toxin P concentration. Toxin P bound avidly to zooxanthellae, such that subsequent addition of NH(4)Cl resulted in rapid inhibition of photosynthesis. When zooxanthellae were incubated in the presence of NH(4)Cl and toxin P, there was a rapid decrease in the pH (pH 7.8 to 7.2) of the bulk liquid, suggesting that toxin P facilitates transport of NH(3) into the cell. It is known that uptake of NH(3) into cells can destroy the pH gradient and block photosynthesis. This mode of action of toxin P can help explain the mechanism of coral bleaching by V. shiloi.
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Affiliation(s)
- E Banin
- Department of Molecular Microbiology & Biotechnology, Tel Aviv University, Ramat Aviv, Israel 69978
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Kundu B, Khare SK. Recent advances in immunosuppressants. Prog Drug Res 1999; 52:1-51. [PMID: 10396125 DOI: 10.1007/978-3-0348-8730-4_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
In recent years, a large number of structurally diverse immunosuppressants have been discovered that are effective for the treatment of organ transplantation. Some of them are undergoing clinical trials and may soon enter into routine clinical practice. These compounds are either chemical entities obtained from natural sources/synthetic means or biomaterials such as monoclonal antibodies/gene products/proteins. They have been found to interfere at different stages of T cell activation and proliferation, and can be identified as inhibitors of nucleotide synthesis, growth factor signal transduction and differentiation. Newer strategies involving combination of new agents with traditional immunosuppressants, monoclonal antibodies and gene therapy offer enormous potential, not only for the investigation of mechanisms pertaining to graft rejection, but also for its therapeutic prevention.
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Affiliation(s)
- B Kundu
- Division of Biopolymers, Central Drug Research Institute, Lucknow, India
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Kundu B, Khare SK, Rastogi SK. Combinatorial chemistry: Polymer supported synthesis of peptide and non-peptide libraries. PROGRESS IN DRUG RESEARCH 1999; 53:89-156. [PMID: 10616297 DOI: 10.1007/978-3-0348-8735-9_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2023]
Abstract
In recent years, combinatorial chemistry has emerged as a powerful tool for accelerating drug discovery. While industry is rapidly embracing the technology, researchers continue to develop novel library methods including resins, linkers, tagging and deconvolution techniques. Newer strategies involving computer-customized combinatorial libraries offer enormous potential for the design of more "focused" and "smart" chemical libraries with maximal diversity. In addition, miniaturized systems for synthesizing chemical libraries are also being developed, which has made it possible to carry out reactions at submicroliter volumes.
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Affiliation(s)
- B Kundu
- Division of Medicinal Chemistry, Central Drug Research Institute, Lucknow, India
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Abstract
Osteoporosis is a common disorder characterized by reduced bone mineral density, deterioration of the microarchitecture of bone tissue and increased risk of fracture. The aim of treatment of osteoporosis is to maintain and, ideally, to restore bone strength safely. In recent years the role of polypeptide growth factors in bone metabolism has begun to appear. It has been proposed that alterations in the expression or production of growth factor can modulate the proliferation and activity of bone forming cells. In this direction, the role of structurally diverse peptides for the management and diagnosis of osteoporosis has attracted the attention of many investigators. This paper reviews numerous findings concerning the use of polypeptides, hormones, and growth factors, for the management of osteoporosis. Many of the compounds mentioned here are experimental prototypes of new therapeutic classes. Though it is unlikely that some of the compounds may ever be used clinically, development of safe and efficacious agents in each class will define the future course of therapy for osteoporosis.
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Affiliation(s)
- B Kundu
- Medicinal Chemistry Division, Central Drug Research Institute, Lucknow, India.
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Abstract
In spite of continuous research in the field of bronchial asthma, still no satisfactory drug is available. Recently a new class of oligopeptide exhibited antiallergic activity by inhibiting the synthesis of IgE antibody. The analogue of ADSDGK (94-335) has shown antiallergic activity in experimental models. The 94-335 inhibited the passive cutaneous anaphylaxis (PCA) reactions in rats in a dose-dependent manner (0.5-10 mg kg-1 p.o.) by 47-90%. There was a 70-87% protection of mast cell degranulation induced by compound 48/80 with peptide 94-335 at 0.5-1.5 mg kg-1 p.o. in rats. This peptide also inhibited antigen- induced contraction in sensitised guinea pig ileum. There was 18 and 72% protection to bronchoconstriction induced by histamine and egg albumin, respectively, in an aerosol test in guinea pigs. These effects of compound 94-335 were comparable with that of the clinically-used antiallergic drug disodium cromoglycate (DSCG). The results suggest that peptide 94-335 possesses potent antiallergic activity.
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Affiliation(s)
- R Singh
- Division of Pharmacology, Central Drug Research Institute, Lucknow, 226001, India
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Srivastava R, Rajput YS, Khare SK, Tyagi R, Gupta MN. Purification and characterization of an acid phosphatase from Arachis hypogaea. Biochem Mol Biol Int 1995; 35:949-56. [PMID: 7549937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
An acid phosphatase from Arachis hypogaea (peanuts) has been purified. The electrophoretically homogeneous enzyme preparation is free of any phophodiesterase activity. The enzyme has a molecular weight of 120,000. Among the various phosphomonoesters tested, p-nitrophenylphosphate was found to be its most effective substrate. The Km for p-nitrophenylphosphate was 1.21 mM at pH 5.0 and 25 degrees C. The enzyme was thermostable and did not loose activity after 1 hr at 50 degrees C.
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