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Aledo JC. Enzyme kinetic parameters estimation: A tricky task? BIOCHEMISTRY AND MOLECULAR BIOLOGY EDUCATION : A BIMONTHLY PUBLICATION OF THE INTERNATIONAL UNION OF BIOCHEMISTRY AND MOLECULAR BIOLOGY 2021; 49:633-638. [PMID: 33900008 DOI: 10.1002/bmb.21522] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 03/17/2021] [Accepted: 04/12/2021] [Indexed: 06/12/2023]
Abstract
We are living in the Big Data era, and yet we may have serious troubles when dealing with a handful of kinetic data if we are not properly instructed. The aim of this paper, related to enzyme kinetics, is to illustrate how to determine the Km and Vmax of a michaelian enzyme avoiding the pitfalls in which we often fall. To this end, we will resort to kinetic data obtained by second-year Biochemistry students during a laboratory experiment using β-galactosidase as an enzyme model, assayed at different concentrations of its substrate. When these data were analyzed using conventional linear regression of double-reciprocal plots, the range of Km and Vmax values obtained by different students varied widely. Even worse, some students obtained negative values for the kinetic parameters. Although such a scenario could make us think of a wide inter-student variability regarding their skills to obtain reliable data, the reality was quite different: when properly analyzed (accounting for error propagation) the data obtained by all the students were good enough to allow a correct estimation of the Km (2.8 ± 0.3 mM) and Vmax (179 ± 27 mM/min) with a reduced intergroup standard deviation. A student-accessible discussion of the importance of weighted linear regression in biochemical sciences is provided.
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Affiliation(s)
- Juan C Aledo
- Departamento de Biología Molecular y Bioquímica. Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
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Wei X, Liu L, Guo X, Wang Y, Zhao J, Zhou S. Light-Activated ROS-Responsive Nanoplatform Codelivering Apatinib and Doxorubicin for Enhanced Chemo-Photodynamic Therapy of Multidrug-Resistant Tumors. ACS APPLIED MATERIALS & INTERFACES 2018; 10:17672-17684. [PMID: 29737828 DOI: 10.1021/acsami.8b04163] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Clinical chemotherapy confronts a challenge resulting from cancer-related multidrug resistance (MDR), which can directly lead to treatment failure. To address it, an innovative approach is proposed to construct a light-activated reactive oxygen species (ROS)-responsive nanoplatform based on a protoporphyrin (PpIX)-conjugated and dual chemotherapeutics-loaded polymer micelle. This system combines chemotherapy and photodynamic therapy (PDT) to defeat the MDR of tumors. Such an intelligent nanocarrier can prolong the circulation time in blood because of the negative polysaccharide component of chondroitin sulfate, and subsequently being selectively internalized by MCF-7/ADR cells [doxorubicin (DOX)-resistant]. When exposed to 635 nm red light, this nanoplatform generates sufficient ROS through the photoconversion of PpIX, further triggering the disassociation of the micelles to release the dual cargoes. Afterward, the released apatinib, serving as a reversal inhibitor of MDR, can recover the chemosensitivity of DOX by competitively inhibiting the P-glycoprotein drug pump in drug-resistant tumor cells, and the excessive ROS has a strong capacity to exert its PDT effect to act on the mitochondria or the nuclei, ultimately causing cell apoptosis. As expected, this intelligent nanosystem successfully reverses tumor MDR via the synergism between apatinib-enhanced DOX sensitivity and ROS-mediated PDT performance.
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Li Z, Han H, Wang B, Gao J, Zhu B, Peng R, Yao Q. Transglucosylation of ascorbic acid to ascorbic acid 2-glucoside by a truncated version of α-glucosidase from Aspergillus niger. J Food Biochem 2017. [DOI: 10.1111/jfbc.12432] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhenjun Li
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Institute; Shanghai Academy of Agricultural Sciences, 2901 Beidi Rd; Shanghai 201106 People's Republic of China
| | - Hongjuan Han
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Institute; Shanghai Academy of Agricultural Sciences, 2901 Beidi Rd; Shanghai 201106 People's Republic of China
| | - Bo Wang
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Institute; Shanghai Academy of Agricultural Sciences, 2901 Beidi Rd; Shanghai 201106 People's Republic of China
| | - Jianjie Gao
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Institute; Shanghai Academy of Agricultural Sciences, 2901 Beidi Rd; Shanghai 201106 People's Republic of China
| | - Bo Zhu
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Institute; Shanghai Academy of Agricultural Sciences, 2901 Beidi Rd; Shanghai 201106 People's Republic of China
| | - Rihe Peng
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Institute; Shanghai Academy of Agricultural Sciences, 2901 Beidi Rd; Shanghai 201106 People's Republic of China
| | - Quanhong Yao
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Institute; Shanghai Academy of Agricultural Sciences, 2901 Beidi Rd; Shanghai 201106 People's Republic of China
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Chen A, Qin X, Tang Y, Liu M, Wang X. Evaluation of enzyme inhibition kinetics in drug–drug interactions. Chem Biol Interact 2014; 222:133-4. [DOI: 10.1016/j.cbi.2014.10.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Revised: 09/27/2014] [Accepted: 10/10/2014] [Indexed: 11/30/2022]
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Deng H, Chen S, Wu D, Chen J, Wu J. Heterologous expression and biochemical characterization of glucose isomerase from Thermobifida fusca. Bioprocess Biosyst Eng 2013; 37:1211-9. [DOI: 10.1007/s00449-013-1093-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 11/07/2013] [Indexed: 11/30/2022]
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Kaewmuangmoon J, Kilaso M, Leartsakulpanich U, Kimura K, Kimura A, Chanchao C. Expression of a secretory α-glucosidase II from Apis cerana indica in Pichia pastoris and its characterization. BMC Biotechnol 2013; 13:16. [PMID: 23419073 PMCID: PMC3599193 DOI: 10.1186/1472-6750-13-16] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 02/14/2013] [Indexed: 11/21/2022] Open
Abstract
Background α–glucosidase (HBGase) plays a key role in hydrolyzing α-glucosidic linkages. In Apis mellifera, three isoforms of HBGase (I, II and III) have been reported, which differ in their nucleotide composition, encoding amino acid sequences and enzyme kinetics. Recombinant (r)HBGase II from A. cerana indica (rAciHBGase II) was focused upon here due to the fact it is a native and economic honeybee species in Thailand. The data is compared to the two other isoforms, AciHBGase I and III from the same bee species and to the three isoforms (HBGase I, II and III) in different bee species where available. Results The highest transcript expression level of AciHBGase II was found in larvae and pupae, with lower levels in the eggs of A. cerana indica but it was not found in foragers. The full-length AciHBGase II cDNA, and the predicted amino acid sequence it encodes were 1,740 bp and 579 residues, respectively. The cDNA sequence was 90% identical to that from the HBGase II from the closely related A. cerana japonica (GenBank accession # NM_FJ752630.1). The full length cDNA was directionally cloned into the pPICZαA expression vector in frame with a (His)6 encoding C terminal tag using EcoRI and KpnI compatible ends, and transformed into Pichia pastoris. Maximal expression of the rAciHBGase II–(His)6 protein was induced by 0.5% (v/v) methanol for 96 h and secreted into the culture media. The partially purified enzyme was found to have optimal α-glucosidase activity at pH 3.5 and 45°C, with > 80% activity between pH 3.5–5.0 and 40–55°C, and was stabile (> 80% activity) at pH 4–8 and at < 25–65°C. The optimal substrate was sucrose. Conclusions Like in A. mellifera, there are three isoforms of AciHBGase (I, II and III) that differ in their transcript expression pattern, nucleotide sequences and optimal enzyme conditions and kinetics.
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Affiliation(s)
- Jirattikarn Kaewmuangmoon
- Program in Biotechnology, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Bangkok 10330, Thailand
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Haddad GL, Young SC, Heindel ND, Bornhop DJ, Flowers RA. Back-Scattering Interferometry: An Ultrasensitive Method for the Unperturbed Detection of Acetylcholinesterase-Inhibitor Interactions. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201203640] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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8
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Haddad GL, Young SC, Heindel ND, Bornhop DJ, Flowers RA. Back-scattering interferometry: an ultrasensitive method for the unperturbed detection of acetylcholinesterase-inhibitor interactions. Angew Chem Int Ed Engl 2012; 51:11126-30. [PMID: 23037915 DOI: 10.1002/anie.201203640] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 08/24/2012] [Indexed: 11/12/2022]
Abstract
A series of inhibitors of acetylcholinesterase (AChE) have been screened by back-scattering interferometry (BSI). Enzyme levels as low as 100 pM (22,000 molecules of AChE) can be detected. This method can be used to screen for mixed AChE inhibitors, agents that have shown high efficacy against Alzheimer's disease, by detecting dual-binding interactions. E = enzyme, I = inhibitor, S = substrate.
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Hidalgo-Cuadrado N, Pérez-Galende P, Manzano T, De Maria CG, Shnyrov VL, Roig MG. Screening of postharvest agricultural wastes as alternative sources of peroxidases: characterization and kinetics of a novel peroxidase from lentil ( Lens culinaris L.) stubble. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:4765-4772. [PMID: 22534011 DOI: 10.1021/jf300245z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Aqueous crude extracts of a series of plant wastes (agricultural, wild plants, residues from sports activities (grass), ornamental residues (gardens)) from 17 different plant species representative of the typical biodiversity of the Iberian peninsula were investigated as new sources of peroxidases (EC 1.11.1.7). Of these, lentil (Lens culinaris L.) stubble crude extract was seen to provide one of the highest specific peroxidase activities, catalyzing the oxidation of guaiacol in the presence of hydrogen peroxide to tetraguaiacol, and was used for further studies. For the optimum extraction conditions found, the peroxidase activity in this crude extract (110 U mL(-1)) did not vary for at least 15 months when stored at 4 °C (k(inact) = 0.146 year(-1), t(1/2 inact) = 4.75 year), whereas, for comparative purposes, the peroxidase activity (60 U mL(-1)) of horseradish (Armoracia rusticana L.) root crude extract, obtained and stored under the same conditions, showed much faster inactivation kinetics (k(inact) = 2.2 × 10(-3) day(-1), t(1/2 inact) = 315 days). Using guaiacol as an H donor and a universal buffer (see above), all crude extract samples exhibited the highest peroxidase activity in the pH range between 4 and 7. Once semipurified by passing the crude extract through hydrophobic chromatography on phenyl-Sepharose CL-4B, the novel peroxidase (LSP) was characterized as having a purity number (RZ) of 2.5 and three SDS-PAGE electrophoretic bands corresponding to molecular masses of 52, 35, and 18 kDa. The steady-state kinetic study carried out on the H(2)O(2)-mediated oxidation of guaiacol by the catalytic action of this partially purified peroxidase pointed to apparent Michaelian kinetic behavior (K(m)(appH(2)O(2)) = 1.87 mM; V(max)(appH(2)O(2)) = 6.4 mM min(-1); K(m)(app guaicol) = 32 mM; V(max)(app guaicol) = 9.1 mM min(-1)), compatible with the two-substrate ping-pong mechanism generally accepted for peroxidases. Finally, after the effectiveness of the crude extracts of LSP in oxidizing and removing from solution a series of last-generation dyes present in effluents from textile industries (1) had been checked, a steady-state kinetic study of the H(2)O(2)-mediated oxidation and decolorization of Green Domalan BL by the catalytic action of the lentil stubble extract was carried out, with the observation of the same apparent Michaelian kinetic behavior (K(m)(appGD) = 471 μM; V(max)(appGD)= 23 μM min(-1)). Further studies are currently under way to address the application of this LSP crude extract for the clinical and biochemical analysis of biomarkers.
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Othman AM, El-Houseini ME, El-Sofy MS, Aboul-Enein HY. Potentiometric determination of α-l-fucosidase enzyme by using 2-chloro-4-nitrophenol-rhodamine B ion pair chemical recognition in PVC membrane sensor. Anal Bioanal Chem 2011; 400:787-95. [DOI: 10.1007/s00216-011-4774-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 02/04/2011] [Accepted: 02/04/2011] [Indexed: 11/29/2022]
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11
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Bueno PR, Watanabe AM, Faria RC, Santos ML, Riccardi CS. Electrogravimetric real-time and in situ michaelis-menten enzymatic kinetics: progress curve of acetylcholinesterase hydrolysis. J Phys Chem B 2010; 114:16605-10. [PMID: 21082796 DOI: 10.1021/jp106274m] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A piezoelectric detection of enzyme-modified surface was performed under Michaelis-Menten presumptions of steady-state condition. The approach herein presented showed promise in the study of enzymatic kinetics by measuring the frequency changes associated with mass changes at the piezoelectric crystal surface. Likewise, real-time frequency shifts, that is, dΔf/dt, indicated the rate of products formation from enzymatic reaction. In this paper, acetylcholinesterase was used as the enzymatic model and acetylcholine as substrate. The enzymatic rate has its maximum value for a short time during the kinetic reaction, for instance, during the first ten minutes of the reaction time scale. The values found for the kinetic constant rate and Michaelis-Menten constant were (1.4 ± 0.8) 10(5) s(-1) and (5.2 ± 3) 10(-4) M, respectively, in agreement with the values found in classical Michaelis-Menten kinetic experiments.
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Affiliation(s)
- Paulo R Bueno
- Instituto de Química, Universidade Estadual Paulista, CP 355, 14800-900, Araraquara, São Paulo, Brasil.
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Mi YJ, Liang YJ, Huang HB, Zhao HY, Wu CP, Wang F, Tao LY, Zhang CZ, Dai CL, Tiwari AK, Ma XX, To KKW, Ambudkar SV, Chen ZS, Fu LW. Apatinib (YN968D1) reverses multidrug resistance by inhibiting the efflux function of multiple ATP-binding cassette transporters. Cancer Res 2010. [PMID: 20876799 DOI: 10.1158/0008-5472.can- 10-0111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Apatinib, a small-molecule multitargeted tyrosine kinase inhibitor, is in phase III clinical trial for the treatment of patients with non-small-cell lung cancer and gastric cancer in China. In this study, we determined the effect of apatinib on the interaction of specific antineoplastic compounds with P-glycoprotein (ABCB1), multidrug resistance protein 1 (MRP1, ABCC1), and breast cancer resistance protein (BCRP, ABCG2). Our results showed that apatinib significantly enhanced the cytotoxicity of ABCB1 or ABCG2 substrate drugs in KBv200, MCF-7/adr, and HEK293/ABCB1 cells overexpressing ABCB1 and in S1-M1-80, MCF-7/FLV1000, and HEK293/ABCG2-R2 cells overexpressing ABCG2 (wild-type). In contrast, apatinib did not alter the cytotoxicity of specific substrates in the parental cells and cells overexpressing ABCC1. Apatinib significantly increased the intracellular accumulation of rhodamine 123 and doxorubicin in the multidrug resistance (MDR) cells. Furthermore, apatinib significantly inhibited the photoaffinity labeling of both ABCB1 and ABCG2 with [(125)I]iodoarylazidoprazosin in a concentration-dependent manner. The ATPase activity of both ABCB1 and ABCG2 was significantly increased by apatinib. However, apatinib, at a concentration that produced a reversal of MDR, did not significantly alter the ABCB1 or ABCG2 protein or mRNA expression levels or the phosphorylation of AKT and extracellular signal-regulated kinase 1/2 (ERK1/2). Importantly, apatinib significantly enhanced the effect of paclitaxel against the ABCB1-resistant KBv200 cancer cell xenografts in nude mice. In conclusion, apatinib reverses ABCB1- and ABCG2-mediated MDR by inhibiting their transport function, but not by blocking the AKT or ERK1/2 pathway or downregulating ABCB1 or ABCG2 expression. Apatinib may be useful in circumventing MDR to other conventional antineoplastic drugs.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B
- ATP Binding Cassette Transporter, Subfamily B, Member 1/drug effects
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- ATP-Binding Cassette Transporters/antagonists & inhibitors
- ATP-Binding Cassette Transporters/drug effects
- Adenosine Triphosphatases/drug effects
- Adenosine Triphosphatases/metabolism
- Animals
- Breast Neoplasms
- Cell Line, Tumor
- Cell Survival/drug effects
- Doxorubicin/pharmacology
- Drug Resistance, Multiple/drug effects
- Enzyme Inhibitors/pharmacology
- Female
- Humans
- Mice
- Mice, Inbred BALB C
- Mice, Nude
- Protein-Tyrosine Kinases/antagonists & inhibitors
- Pyridines/therapeutic use
- Reverse Transcriptase Polymerase Chain Reaction
- Transplantation, Heterologous
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Affiliation(s)
- Yan-Jun Mi
- State Key Laboratory of Oncology in South China, Cancer Center, Sun Yat-Sen University, Guangzhou, China
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Mi YJ, Liang YJ, Huang HB, Zhao HY, Wu CP, Wang F, Tao LY, Zhang CZ, Dai CL, Tiwari AK, Ma XX, To KKW, Ambudkar SV, Chen ZS, Fu LW. Apatinib (YN968D1) reverses multidrug resistance by inhibiting the efflux function of multiple ATP-binding cassette transporters. Cancer Res 2010; 70:7981-91. [PMID: 20876799 DOI: 10.1158/0008-5472.can-10-0111] [Citation(s) in RCA: 273] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Apatinib, a small-molecule multitargeted tyrosine kinase inhibitor, is in phase III clinical trial for the treatment of patients with non-small-cell lung cancer and gastric cancer in China. In this study, we determined the effect of apatinib on the interaction of specific antineoplastic compounds with P-glycoprotein (ABCB1), multidrug resistance protein 1 (MRP1, ABCC1), and breast cancer resistance protein (BCRP, ABCG2). Our results showed that apatinib significantly enhanced the cytotoxicity of ABCB1 or ABCG2 substrate drugs in KBv200, MCF-7/adr, and HEK293/ABCB1 cells overexpressing ABCB1 and in S1-M1-80, MCF-7/FLV1000, and HEK293/ABCG2-R2 cells overexpressing ABCG2 (wild-type). In contrast, apatinib did not alter the cytotoxicity of specific substrates in the parental cells and cells overexpressing ABCC1. Apatinib significantly increased the intracellular accumulation of rhodamine 123 and doxorubicin in the multidrug resistance (MDR) cells. Furthermore, apatinib significantly inhibited the photoaffinity labeling of both ABCB1 and ABCG2 with [(125)I]iodoarylazidoprazosin in a concentration-dependent manner. The ATPase activity of both ABCB1 and ABCG2 was significantly increased by apatinib. However, apatinib, at a concentration that produced a reversal of MDR, did not significantly alter the ABCB1 or ABCG2 protein or mRNA expression levels or the phosphorylation of AKT and extracellular signal-regulated kinase 1/2 (ERK1/2). Importantly, apatinib significantly enhanced the effect of paclitaxel against the ABCB1-resistant KBv200 cancer cell xenografts in nude mice. In conclusion, apatinib reverses ABCB1- and ABCG2-mediated MDR by inhibiting their transport function, but not by blocking the AKT or ERK1/2 pathway or downregulating ABCB1 or ABCG2 expression. Apatinib may be useful in circumventing MDR to other conventional antineoplastic drugs.
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Affiliation(s)
- Yan-Jun Mi
- State Key Laboratory of Oncology in South China, Cancer Center, Sun Yat-Sen University, Guangzhou, China
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Li P, Zhu CL, Zhang XX, Gan L, Yu HZ, Gan Y. Reversible inhibitory effects of saturated and unsaturated alkyl esters on the carboxylesterases activity in rat intestine. Lipids 2010; 45:603-12. [PMID: 20532832 DOI: 10.1007/s11745-010-3434-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Accepted: 05/19/2010] [Indexed: 10/19/2022]
Abstract
This study was conducted to investigate the relationship between the carbon chain length/double bonds of alkyl esters and their inhibitory potency/mechanism on carboxylesterases (CESs). CESs activity was evaluated by inhibition of adefovir dipivoxil (ADV) metabolism in rat intestinal homogenates. Furthermore, the inhibitory effect of BNPP and ethyl (E)-hex-2-enoate (C8:1) on drug absorption was evaluated in situ intestinal perfusion model. The results showed that the rank order of the inhibitory potency on CESs was C10:0 > C8:0 > C6:0 > C4:0 > C12:0, C8:1 > C8:0, C6:1 > C6:0, while the esters (C14:0, C13:1, C16:0, C18:0, C17:1, C20:0) were found to have no inhibitory effect at investigated concentrations. However, the unsaturated esters (C20:1, C20:2, C20:3) displayed the inhibitory effect on CESs. Moreover, the double reciprocal plots indicated that alky esters inhibited the CESs in competitive and mixed competitive ways which were reversible. In addition, the result of most effective CESs inhibitor C8:1 from in situ experiment showed that C8:1 can inhibit the CESs-mediated intestinal metabolism and improve the drug absorption. And the inhibition had no time-dependent effect, compared with that of BNPP groups. The study suggested that alkyl esters can be served as effective and reversible CESs inhibitors, besides that their inhibitory potency/mechanism can be affected by their carbon chain length/double bonds.
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Affiliation(s)
- Ping Li
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai, 201203, China
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Chen DL, Tong X, Chen SW, Chen S, Wu D, Fang SG, Wu J, Chen J. Heterologous expression and biochemical characterization of alpha-glucosidase from Aspergillus niger by Pichia pastroris. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:4819-4824. [PMID: 20369871 DOI: 10.1021/jf1000502] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The aglu of Aspergillus niger encodes the pro-protein of alpha-glucosidase, and the mature form of wild-type enzyme is a heterosubunit protein. In the present study, the cDNA of alpha-glucosidase was cloned and expressed in Pichia pastoris strain KM71. The activity of recombinant enzyme in a 3 L fermentor reached 2.07 U/mL after 96 h of induction. The recombinant alpha-glucosidase was able to produce oligoisomaltose. The molecular weight of the recombinant enzyme was estimated to be about 145 kDa by SDS-PAGE, and it reduced to 106 kDa after deglycosylation. The enzymatic activity of recombinant alpha-glucosidase was not significantly affected by a range of metal ions. The optimum temperature of the enzyme was 60 degrees C, and it was stable below 50 degrees C. The enzyme was active over the range of pH 3.0-7.0 with maximal activity at pH 4.5. Using pNPG as substrate, the K(m) and V(max) values were 0.446 mM and 43.48 U/mg, respectively. These studies provided the basis for the application of recombinant alpha-glucosidase in the industry of functional oligosaccharides.
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Affiliation(s)
- Dong-Li Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenve, Wuxi 214122, People's Republic of China
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Determination of specific activities and kinetic constants of biotinidase and lipoamidase in LEW rat and Lactobacillus casei (Shirota). J Chromatogr B Analyt Technol Biomed Life Sci 2006; 844:240-50. [PMID: 16876490 DOI: 10.1016/j.jchromb.2006.07.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Revised: 06/27/2006] [Accepted: 07/11/2006] [Indexed: 11/25/2022]
Abstract
Enzyme kinetic parameters, such as K(m), V(max) (or V), k(cat)/K(m), and K(i) (by biotin or lipoic acid) for biotinidase and lipoamidase were determined in Lewis (LEW) rat and Lactobacillus casei (Shirota) using fluorimetric high-performance liquid chromatography (HPLC). It was found that the final protein concentration below 0.1mg/ml is sufficient to obtain linear hydrolytic reaction and to determine the Michaelis-Menten type kinetic parameters (K(m), V, K(i)). We applied this HPLC enzyme assay method onto the rat and some bacteria. The highest specific activities (Vs) for biotinidase were found in Lactobacillus casei (Shirota) and rat kidney. It was also found that the largest K(i) by product for biotinidase and lipoamidase were present in the Lactobacillus casei (Shirota). There has been found specie (between rat and mouse) differences and tissue (organ) differences, together with tissue region differences and sex differences in some tissues. Summary of the distributions of both enzymes in LEW rat was also presented. Therefore, this HPLC determination method for the enzyme kinetic parameters in tissues is expected to be an indispensable tool for the investigation of the various diseases in humans.
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Model MA, Healy KE. Optimization of the cost and sensitivity of receptor- and enzyme-based assays. Anal Biochem 1999; 271:59-69. [PMID: 10361005 DOI: 10.1006/abio.1999.4122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In detecting receptor antagonists or enzyme inhibitors, there are three parameters that often affect the outcome in a predictable quantitative manner: concentrations of the receptors (enzyme), labeled ligand (substrate), and antagonist (inhibitor). The usual goal of assay optimization is to maximize the ability of the assay to detect low concentrations of the analyte. Another question of practical importance, especially in screening of large numbers of samples, would be minimization of the reagent cost. Although the mathematical theory of optimization of the receptor binding assay was developed a long time ago, the resulting formulas (in the general case of unequal affinities of ligand and competitor) were not well suited for practical use. The current availability of computational programs, such as Mathematica, makes possible an efficient solution, both for receptor- and enzyme-based assays. We use a graphical approach to assay optimization and apply it to the following problems: (1) optimization of assay sensitivity, (2) optimization of the reagent cost, and (3) analysis of the entire range of the parameter values since the mathematically optimal values may sometimes be impractical. The computation is extremely simple and the problem can sometimes be solved in several minutes.
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Affiliation(s)
- M A Model
- Division of Biological Materials, Northwestern University, Chicago, Illinois 60611, USA.
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Abstract
A model of substrate inhibition for enzyme catalysis was extended to describe the kinetics of photosynthetic production of ethylene by a recombinant cyanobacterium, which exhibits light-inhibition behavior similar to the substrate-inhibition behavior in enzyme reactions. To check the validity of the model against the experimental data, the model equation, which contains three kinetic parameters, was transformed so that a linear plot of the data could be made. The plot yielded reasonable linearity, and the parameter values could be estimated from the plot. The linear-plot approach was then applied to other inhibition kinetics including substrate inhibition of enzyme reactions and inhibitory growth of bacteria, whose analyses would otherwise require nonlinear least-squares fits or data measured in constrained ranges. Plots for three totally different systems all showed reasonable linearity, which enabled visual validation of the assumed kinetics. Parameter values evaluated from the plots were compared with results of nonlinear least-squares fits. A normalized linear plot for all the results discussed in this work is also presented, where dimensionless rates as a function of dimensionless concentration lie in a straight line. The linear-plot approach is expected to be complementary to nonlinear least-squares fits and other currently used methods in analyses of substrate-inhibition kinetics. Copyright 1999 John Wiley & Sons, Inc.
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Affiliation(s)
- J Wang
- Shiga Technology Center, Iwatani International Corporation, Moriyama, 524 Japan
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Bowser MT, Chen DDY. Monte Carlo Simulation of Error Propagation in the Determination of Binding Constants from Rectangular Hyperbolae. 2. Effect of the Maximum-Response Range. J Phys Chem A 1998. [DOI: 10.1021/jp982917e] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michael T. Bowser
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, Canada V6T 1Z1
| | - David D. Y. Chen
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, Canada V6T 1Z1
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Bowser MT, Chen DDY. Monte Carlo Simulation of Error Propagation in the Determination of Binding Constants from Rectangular Hyperbolae. 1. Ligand Concentration Range and Binding Constant. J Phys Chem A 1998. [DOI: 10.1021/jp9819947] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Michael T. Bowser
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
| | - David D. Y. Chen
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
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Ritchie RJ, Prvan T. Current statistical methods for estimating the Km and Vmax of Michaelis-Menten kinetics. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s0307-4412(96)00089-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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22
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Cornish-Bowden A. Parameter estimating procedures for the Michaelis-Menten model: reply to Tseng and Hsu. J Theor Biol 1991; 153:437-40. [PMID: 1798339 DOI: 10.1016/s0022-5193(05)80580-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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