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Wei Z, Zhao Y, Zhao L, Wang L, Wu J. The contribution of microbial shikimic acid to humus formation during organic wastes composting: a review. World J Microbiol Biotechnol 2023; 39:240. [PMID: 37392253 DOI: 10.1007/s11274-023-03674-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 06/08/2023] [Indexed: 07/03/2023]
Abstract
Microbial shikimic acid is an important intermediate metabolite in the synthesis of aromatic amino acids which are precursors for forming humus during composting process. Generally, the pathways producing shikimic acid and its downstream products are collectively referred as shikimic acid pathway (SKP). Microbial SKP can produce phenols, and tyrosine. Pyrogallol is the precursor of phenols. And, tyrosine can form an ammoniated monomer. Therefore, regulation of SKP can promote shikimic acid production, which is beneficial in promoting humus production and humification. However, SKP present in microbial cells is distinctive because of providing precursors for humification process, which needs to be recognized during composting. Due to the different structures of various organic wastes, it is difficult to control the SKP efficiency and shikimic acid production. Therefore, it is valuable to review the synthesis of shikimic acid by microorganisms and propose how to promote SKP during different materials composting. Furthermore, we have attempted to illustrate the application of metabolites from SKP in forming humus during organic waste composting. Finally, a series of regulating methods has been outlined to enhance microbial SKP, which are effective to promote humus aromatization and to improve humus formation during different materials composting.
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Affiliation(s)
- Zimin Wei
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, Tianjin, 300387, China
| | - Yue Zhao
- College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Li Zhao
- College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Liqin Wang
- College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Junqiu Wu
- College of Life Science, Northeast Agricultural University, Harbin, 150030, China.
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2
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Torul H, Çalık Kayiş E, Boyaci IH, Tamer U. An ECL sensor combined with a paper electrode for the determination of phenylalanine. Analyst 2022; 147:4866-4875. [DOI: 10.1039/d2an01340a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
An electrochemiluminescence (ECL) sensor combined with a paper electrode was developed for the detection of phenylalanine (l-Phe) in blood samples.
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Affiliation(s)
- Hilal Torul
- Faculty of Pharmacy, Department of Analytical Chemistry, Gazi University, 06330 Ankara, Turkey
| | - Elif Çalık Kayiş
- Faculty of Pharmacy, Department of Analytical Chemistry, Gazi University, 06330 Ankara, Turkey
| | - I. Hakki Boyaci
- Department of Food Engineering, Hacettepe University, Beytepe, 06512 Ankara, Turkey
| | - Ugur Tamer
- Faculty of Pharmacy, Department of Analytical Chemistry, Gazi University, 06330 Ankara, Turkey
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Xiao H, Liu P, Zheng S, Wang X, Ding J, Feng Y. Screening of amino acids in dried blood spots by stable isotope derivatization-liquid chromatography-electrospray ionization mass spectrometry. CHINESE CHEM LETT 2020. [DOI: 10.1016/j.cclet.2020.03.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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5
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Liu YH, Du TT, Wan JY, Zhao H, Huang D, Li JS, Jiang XH. Simultaneous determination of thirteen substances related to NAFLD in mouse brain tissue using 3-aminobutyric acid as internal standard by HPLC-FLD. Biomed Chromatogr 2019; 34:e4767. [PMID: 31785600 DOI: 10.1002/bmc.4767] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 10/29/2019] [Accepted: 11/26/2019] [Indexed: 12/17/2022]
Abstract
Disorders of certain branched-chain amino acids may be associated with the occurrence and development of non-alcoholic fatty liver disease. Measurement of related branched-chain amino acid levels could provide a reference for the clinical and scientific research of the non-alcoholic fatty liver disease. An established HPLC-FLD method was used to quantify aspartic acid, glutamate, glutamine, glycine, taurine, tyrosine, 4-amino butanoic acid, tryptophan, methionine, valine, phenylalanine, isoleucine and leucine in mouse brain tissue. Brain tissue samples mixed with internal standard (3-aminobutyric acid) were processed, then derivatized with 2-O-phthaldialdehyde, and finally separated on an ODS2 column through gradient elution at a flow rate of 1.0 ml·min-1 . The excitation and emission wavelengths were set at 340 and 455 nm, respectively. The mobile phase A was 100% methanol and the mobile phase B consisted of 30 mmol·L-1 sodium acetate (pH 6.8). The injection volume was 20 μl and the single run time was 45 min. Several parameters, accuracy, precision, and stability, were verified and the results showed the established method had good sensitivity and resolution for all of the 13 compounds and internal standard in mouse brain.
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Affiliation(s)
- Yong-Hong Liu
- School of Pharmacy, Chongqing Medical University, Chongqing, China
| | - Ting-Ting Du
- School of Pharmacy, Chongqing Medical University, Chongqing, China
| | - Jing-Yuan Wan
- School of Pharmacy, Chongqing Medical University, Chongqing, China
| | - Hua Zhao
- School of Pharmacy, Chongqing Medical University, Chongqing, China
| | - Dan Huang
- Pengzhou People's hospital, Sichuan Province, China
| | - Jian-Sha Li
- School of Pharmacy, Chongqing Medical University, Chongqing, China
| | - Xin-Hui Jiang
- School of Pharmacy, Chongqing Medical University, Chongqing, China
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Baruteau J, Khalil Y, Grunewald S, Zancolli M, Chakrapani A, Cleary M, Davison J, Footitt E, Waddington SN, Gissen P, Mills P. Urea Cycle Related Amino Acids Measured in Dried Bloodspots Enable Long-Term In Vivo Monitoring and Therapeutic Adjustment. Metabolites 2019; 9:E275. [PMID: 31718089 PMCID: PMC6918381 DOI: 10.3390/metabo9110275] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 10/19/2019] [Accepted: 11/05/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Dried bloodspots are easy to collect and to transport to assess various metabolites, such as amino acids. Dried bloodspots are routinely used for diagnosis and monitoring of some inherited metabolic diseases. METHODS Measurement of amino acids from dried blood spots by liquid chromatography-tandem mass spectrometry. RESULTS We describe a novel rapid method to measure underivatised urea cycle related amino acids. Application of this method enabled accurate monitoring of these amino acids to assess the efficacy of therapies in argininosuccinate lyase deficient mice and monitoring of these metabolites in patients with urea cycle defects. CONCLUSION Measuring urea cycle related amino acids in urea cycle defects from dried blood spots is a reliable tool in animal research and will be of benefit in the clinic, facilitating optimisation of protein-restricted diet and preventing amino acid deprivation.
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Affiliation(s)
- Julien Baruteau
- Genetics and Genomic Medicine, Great Ormond Street Institute of Child Health, University College London, London WC1E 6BT, UK; (Y.K.); (P.G.); (P.M.)
- Gene Transfer Technology Group, Institute for Women’s Health, University College London, London WC1E 6BT, UK;
- Metabolic Medicine Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK; (S.G.); (A.C.); (M.C.); (J.D.); (E.F.)
- National Institute of Health Research Great Ormond Street Hospital Biomedical Research Centre, London W1T 7HA, UK;
| | - Youssef Khalil
- Genetics and Genomic Medicine, Great Ormond Street Institute of Child Health, University College London, London WC1E 6BT, UK; (Y.K.); (P.G.); (P.M.)
| | - Stephanie Grunewald
- Metabolic Medicine Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK; (S.G.); (A.C.); (M.C.); (J.D.); (E.F.)
| | - Marta Zancolli
- National Institute of Health Research Great Ormond Street Hospital Biomedical Research Centre, London W1T 7HA, UK;
| | - Anupam Chakrapani
- Metabolic Medicine Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK; (S.G.); (A.C.); (M.C.); (J.D.); (E.F.)
| | - Maureen Cleary
- Metabolic Medicine Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK; (S.G.); (A.C.); (M.C.); (J.D.); (E.F.)
| | - James Davison
- Metabolic Medicine Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK; (S.G.); (A.C.); (M.C.); (J.D.); (E.F.)
| | - Emma Footitt
- Metabolic Medicine Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK; (S.G.); (A.C.); (M.C.); (J.D.); (E.F.)
| | - Simon N. Waddington
- Gene Transfer Technology Group, Institute for Women’s Health, University College London, London WC1E 6BT, UK;
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2000, South Africa
| | - Paul Gissen
- Genetics and Genomic Medicine, Great Ormond Street Institute of Child Health, University College London, London WC1E 6BT, UK; (Y.K.); (P.G.); (P.M.)
- Gene Transfer Technology Group, Institute for Women’s Health, University College London, London WC1E 6BT, UK;
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Philippa Mills
- Genetics and Genomic Medicine, Great Ormond Street Institute of Child Health, University College London, London WC1E 6BT, UK; (Y.K.); (P.G.); (P.M.)
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Li Z, Wu J, Jia L. Analysis of amino acids in blood by combining zeolitic imidazolate framework-8-based solid phase extraction and capillary electrophoresis. J Pharm Biomed Anal 2019; 168:30-37. [DOI: 10.1016/j.jpba.2019.02.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 02/11/2019] [Accepted: 02/12/2019] [Indexed: 02/05/2023]
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Protein Quantification by Derivatization-Free High-Performance Liquid Chromatography of Aromatic Amino Acids. JOURNAL OF AMINO ACIDS 2016; 2016:7374316. [PMID: 27559481 PMCID: PMC4983383 DOI: 10.1155/2016/7374316] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 06/28/2016] [Indexed: 11/22/2022]
Abstract
Amino acid analysis is considered to be the gold standard for quantitative peptide and protein analysis. Here, we would like to propose a simple HPLC/UV method based on a reversed-phase separation of the aromatic amino acids tyrosine (Tyr), phenylalanine (Phe), and optionally tryptophan (Trp) without any derivatization. The hydrolysis of the proteins and peptides was performed by an accelerated microwave technique, which needs only 30 minutes. Two internal standard compounds, homotyrosine (HTyr) and 4-fluorophenylalanine (FPhe) were used for calibration. The limit of detection (LOD) was estimated to be 0.05 µM (~10 µg/L) for tyrosine and phenylalanine at 215 nm. The LOD for a protein determination was calculated to be below 16 mg/L (~300 ng BSA absolute). Aromatic amino acid analysis (AAAA) offers excellent accuracy and a precision of about 5% relative standard deviation, including the hydrolysis step. The method was validated with certified reference materials (CRM) of amino acids and of a pure protein (bovine serum albumin, BSA). AAAA can be used for the quantification of aromatic amino acids, isolated peptides or proteins, complex peptide or protein samples, such as serum or milk powder, and peptides or proteins immobilized on solid supports.
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Tiwari JN, Vij V, Kemp KC, Kim KS. Engineered Carbon-Nanomaterial-Based Electrochemical Sensors for Biomolecules. ACS NANO 2016; 10:46-80. [PMID: 26579616 DOI: 10.1021/acsnano.5b05690] [Citation(s) in RCA: 266] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The study of electrochemical behavior of bioactive molecules has become one of the most rapidly developing scientific fields. Biotechnology and biomedical engineering fields have a vested interest in constructing more precise and accurate voltammetric/amperometric biosensors. One rapidly growing area of biosensor design involves incorporation of carbon-based nanomaterials in working electrodes, such as one-dimensional carbon nanotubes, two-dimensional graphene, and graphene oxide. In this review article, we give a brief overview describing the voltammetric techniques and how these techniques are applied in biosensing, as well as the details surrounding important biosensing concepts of sensitivity and limits of detection. Building on these important concepts, we show how the sensitivity and limit of detection can be tuned by including carbon-based nanomaterials in the fabrication of biosensors. The sensing of biomolecules including glucose, dopamine, proteins, enzymes, uric acid, DNA, RNA, and H2O2 traditionally employs enzymes in detection; however, these enzymes denature easily, and as such, enzymeless methods are highly desired. Here we draw an important distinction between enzymeless and enzyme-containing carbon-nanomaterial-based biosensors. The review ends with an outlook of future concepts that can be employed in biosensor fabrication, as well as limitations of already proposed materials and how such sensing can be enhanced. As such, this review can act as a roadmap to guide researchers toward concepts that can be employed in the design of next generation biosensors, while also highlighting the current advancements in the field.
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Affiliation(s)
- Jitendra N Tiwari
- Center for Superfunctional Materials, Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 689-798, Korea
| | - Varun Vij
- Center for Superfunctional Materials, Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 689-798, Korea
| | - K Christian Kemp
- Center for Superfunctional Materials, Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 689-798, Korea
| | - Kwang S Kim
- Center for Superfunctional Materials, Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 689-798, Korea
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10
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Attia MS, Yakout AA. Novel method for tyrosine assessment in vitro using luminescence quenching of the nano optical sensor Eu–ciprofloxacin doped in a sol–gel matrix. RSC Adv 2016. [DOI: 10.1039/c5ra25301b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A low cost and very sensitive method for the assessment of tyrosine in blood serum, urine and hair samples was developed. The method was based upon the luminescence intensity of a Eu–ciprofloxacin complex nano optical sensor.
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Affiliation(s)
- M. S. Attia
- Chemistry Department
- Faculty of Science
- University of Jeddah
- Jeddah
- Saudi Arabia
| | - Amr A. Yakout
- Chemistry Department
- Faculty of Science
- University of Jeddah
- Jeddah
- Saudi Arabia
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11
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Li G, Yang M, Chen LC, Gao B, Xiong XL. Colorimetric and visual detection of tyrosine based on its copper-catalyzed enzymatic oxidation to dopamine and subsequent reductive formation of colored gold nanoparticles using copper ions. Mikrochim Acta 2014. [DOI: 10.1007/s00604-014-1278-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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12
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Keyvanfard M, Tahmasbi M, Karimi-Maleh H, Alizad K. A voltammetric sensor with a multiwall carbon nanotube paste electrode and naphthol green as a mediator for the determination of N-actylcysteine in the presence of tryptophan. CHINESE JOURNAL OF CATALYSIS 2014. [DOI: 10.1016/s1872-2067(14)60019-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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13
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Analysis of amino acid composition in proteins of animal tissues and foods as pre-column o-phthaldialdehyde derivatives by HPLC with fluorescence detection. J Chromatogr B Analyt Technol Biomed Life Sci 2014; 964:116-27. [PMID: 24731621 DOI: 10.1016/j.jchromb.2014.03.025] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 03/21/2014] [Accepted: 03/22/2014] [Indexed: 01/15/2023]
Abstract
Studies of protein nutrition and biochemistry require reliable methods for analysis of amino acid (AA) composition in polypeptides of animal tissues and foods. Proteins are hydrolyzed by 6M HCl (110°C for 24h), 4.2M NaOH (105°C for 20 h), or proteases. Analytical techniques that require high-performance liquid chromatography (HPLC) include pre-column derivatization with 4-chloro-7-nitrobenzofurazan, 9-fluorenyl methylchloroformate, phenylisothiocyanate, naphthalene-2,3-dicarboxaldehyde, 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate, and o-phthaldialdehyde (OPA). OPA reacts with primary AA (except cysteine or cystine) in the presence of 2-mercaptoethanol or 3-mercaptopropionic acid to form a highly fluorescent adduct. OPA also reacts with 4-amino-1-butanol and 4-aminobutane-1,3-diol produced from oxidation of proline and 4-hydroxyproline, respectively, in the presence of chloramine-T plus sodium borohydride at 60°C, or with S-carboxymethyl-cysteine formed from cysteine and iodoacetic acid at 25°C. Fluorescence of OPA derivatives is monitored at excitation and emission wavelengths of 340 and 455 nm, respectively. Detection limits are 50 fmol for AA. This technique offers the following advantages: simple procedures for preparation of samples, reagents, and mobile-phase solutions; rapid pre-column formation of OPA-AA derivatives and their efficient separation at room temperature (e.g., 20-25°C); high sensitivity of detection; easy automation on the HPLC apparatus; few interfering side reactions; a stable chromatography baseline for accurate integration of peak areas; and rapid regeneration of guard and analytical columns. Thus, the OPA method provides a useful tool to determine AA composition in proteins of animal tissues (e.g., skeletal muscle, liver, intestine, placenta, brain, and body homogenates) and foods (e.g., milk, corn grain, meat, and soybean meal).
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Majd SM, Teymourian H, Salimi A. Fabrication of an ElectrochemicalL-Cysteine Sensor Based on Graphene Nanosheets Decorated Manganese Oxide Nanocomposite Modified Glassy Carbon Electrode. ELECTROANAL 2013. [DOI: 10.1002/elan.201300245] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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15
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Mo XM, Li Y, Tang AG, Ren YP. Simultaneous determination of phenylalanine and tyrosine in peripheral capillary blood by HPLC with ultraviolet detection. Clin Biochem 2013; 46:1074-1078. [DOI: 10.1016/j.clinbiochem.2013.05.047] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Revised: 04/22/2013] [Accepted: 05/15/2013] [Indexed: 10/26/2022]
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16
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Newborn screening of phenylketonuria using direct analysis in real time (DART) mass spectrometry. Anal Bioanal Chem 2013; 405:3159-64. [DOI: 10.1007/s00216-013-6713-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 12/16/2012] [Accepted: 01/09/2013] [Indexed: 10/27/2022]
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17
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Ghoreishi SM, Behpour M, Jafari N, Golestaneh M. Electrochemical Determination of Tyrosine in the Presence of Dopamine and Uric Acid at the Surface of Gold Nanoparticles Modified Carbon Paste Electrode. J CHIN CHEM SOC-TAIP 2012. [DOI: 10.1002/jccs.201100654] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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18
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Lu J, Ge S, Wan F, Yu J. Detection of L-phenylalanine using molecularly imprinted solid-phase extraction and flow injection electrochemiluminescence. J Sep Sci 2011; 35:320-6. [DOI: 10.1002/jssc.201100787] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 10/20/2011] [Accepted: 10/20/2011] [Indexed: 11/10/2022]
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Cheng ML, Tsai BC, Yang J. Silver nanoparticle-treated filter paper as a highly sensitive surface-enhanced Raman scattering (SERS) substrate for detection of tyrosine in aqueous solution. Anal Chim Acta 2011; 708:89-96. [PMID: 22093349 DOI: 10.1016/j.aca.2011.10.013] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2011] [Revised: 10/01/2011] [Accepted: 10/09/2011] [Indexed: 11/24/2022]
Abstract
Highly sensitive SERS substrates based on deposition of silver nanoparticles on commercially available filter paper were prepared in this work, and used to overcome problems found in analyses of aqueous samples. To prepare silver nanoparticle- (AgNP) doped filter substrates, a silver mirror reaction was used. The procedures for substrate preparation were systematically optimized. Pretreatment of filter paper, reaction time, temperature, and concentration of reagents for silver mirror reactions were studied. The morphologies of the resulting substrates were characterized by field-emission scanning electron microscopy (FE-SEM) and correlated with the SERS signals by probing with p-nitrothiophenol (pNTP). Filter papers with different pretreatments were found to have different sizes and distributions of AgNPs. The best performance was found when filter paper was pre-treated with ammonia solution before growth of AgNPs. Based on the SEM images, the resulting AgNPs had roughly spherical shape with a high degree of uniformity. The silver-coated filter paper substrates provide much higher SERS signals compared to glass substrates and the reproducibility was improved significantly. Based on statistical analyses, the relative standard deviations for substrate-to-substrate and spot-to-spot were both were less than 8% and the enhancement factors for the substrates were, in general, higher than 107. The SERS substrates were used to selectively detect tyrosine in aqueous solution. Results indicate that filter-based SERS substrates are highly suited to detection of tyrosine. Compared to glass-based SERS substrates, 50 times more SERS signal was observed in detection of tyrosine. The linear range can be up to 100 μM with a detection limit of 625 nM (SN(-1)=3).
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Affiliation(s)
- Min-Liang Cheng
- Department of Chemistry, National Chung-Hsing University, Taichung 402, Taiwan
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Prabhu P, Babu RS, Narayanan SS. Electrocatalytic oxidation of l-tryptophan using copper hexacyanoferrate film modified gold nanoparticle graphite-wax electrode. Colloids Surf B Biointerfaces 2011; 87:103-8. [DOI: 10.1016/j.colsurfb.2011.05.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 04/30/2011] [Accepted: 05/03/2011] [Indexed: 11/25/2022]
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21
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Effect of surface modification of indium tin oxide by nanoparticles on the electrochemical determination of tryptophan. Talanta 2011; 85:2626-31. [DOI: 10.1016/j.talanta.2011.08.031] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Revised: 08/15/2011] [Accepted: 08/15/2011] [Indexed: 11/21/2022]
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22
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Li CF, Du LM, Wu H, Chang YX. Determination of l-phenylalanine by cucurbit[7]uril sensitized fluorescence quenching method. CHINESE CHEM LETT 2011. [DOI: 10.1016/j.cclet.2010.12.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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23
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A simple method for the analysis by MS/MS of underivatized amino acids on dry blood spots from newborn screening. Amino Acids 2011; 42:1889-95. [DOI: 10.1007/s00726-011-0910-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Accepted: 04/01/2011] [Indexed: 10/18/2022]
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24
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Matsuda M, Asano Y. Determination of plasma and serum l-lysine using l-lysine ε-oxidase from Marinomonas mediterranea NBRC 103028T. Anal Biochem 2010; 406:19-23. [DOI: 10.1016/j.ab.2010.06.045] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 06/21/2010] [Accepted: 06/27/2010] [Indexed: 11/25/2022]
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25
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Zhu X, Xu S. Determination of L-tyrosine by beta-cyclodextrin sensitized fluorescence quenching method. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2010; 77:566-571. [PMID: 20667765 DOI: 10.1016/j.saa.2010.04.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 04/07/2010] [Accepted: 04/28/2010] [Indexed: 05/29/2023]
Abstract
A novel beta-cyclodextrin (beta-CD) sensitized fluorescence quenching method for the determination of l-tyrosine (l-Tyr) with Mo(VI)-phenyl-fluorone (PF) as a fluorescence probe has been developed. The fluorescence intensity of Mo(VI)-PF-beta-CD was diminished as the l-tyrosine was added, the fluorescence quenching value DeltaF=F(beta-CD-Mo-PF)-F(beta-CD-Mo-PF-l-Tyr) was enhanced in beta-CD and there was a linear relationship between the DeltaF and the concentration of l-Tyr. Under the optimal conditions, the linear range of calibration curve for the determination of l-tyrosine was 0.3-20.0microgmL(-1); the detection limit was 0.094microgmL(-1). NaOH (10%, w/v) is the best reagent of hydrolysis in sample preparation. The sensitized mechanism of beta-cyclodextrin was discussed. The method has been applied to the determination of l-tyrosine in spirulina and food samples with satisfactory results.
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Affiliation(s)
- Xiashi Zhu
- Department of Chemistry, Yangzhou University, Yangzhou, Jiangsu 225002, People's Republic of China.
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Srivastava AK, Gaichore RR. Macrocyclic Compounds Based Chemically Modified Electrodes for Voltammetric Determination of L-Tryptophan Using Electrocatalytic Oxidation. ANAL LETT 2010. [DOI: 10.1080/00032711003687005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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27
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Gold nanoparticle/carbon nanotube hybrids as an enhanced material for sensitive amperometric determination of tryptophan. Electrochim Acta 2010. [DOI: 10.1016/j.electacta.2010.02.024] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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De Silva V, Oldham CD, May SW. L-Phenylalanine concentration in blood of phenylketonuria patients: a modified enzyme colorimetric assay compared with amino acid analysis, tandem mass spectrometry, and HPLC methods. Clin Chem Lab Med 2010; 48:1271-9. [DOI: 10.1515/cclm.2010.271] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Kand'ár R, Záková P. Determination of phenylalanine and tyrosine in plasma and dried blood samples using HPLC with fluorescence detection. J Chromatogr B Analyt Technol Biomed Life Sci 2009; 877:3926-9. [PMID: 19836316 DOI: 10.1016/j.jchromb.2009.09.045] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Revised: 07/30/2009] [Accepted: 09/29/2009] [Indexed: 11/29/2022]
Abstract
The determination of phenylalanine and tyrosine is presently the most reliable direct approach to the diagnosis of phenylketonuria. An HPLC method for the simultaneous measurement of phenylalanine and tyrosine in samples of dried blood spots and plasma has been developed and evaluated. We have used an inherent fluorescence of both phenylalanine and tyrosine. For the separation, a reverse-phase column LiChroCart 125-4, Purospher RP-18e, 5microm, was used. The mixture of ethanol and deionized water (5:95, v/v) was used as a mobile phase. Analytical performance of this method is satisfactory for both phenylalanine and tyrosine: the intra-assay and inter-assay coefficients of variation were below 10%. Quantitative recoveries from spiked plasma and blood samples were between 92.0 and 102.9%. The limit of detection was 10.0 and 5.0micromol/L, respectively. The preliminary reference ranges of phenylalanine and tyrosine in a group of newborns are 69.3+/-13.1 and 42.7+/-12.9micromol/L, in a group of blood donors are 68.4+/-9.9 and 52.1+/-10.9micromol/L. The presented method is inexpensive and suitable for diagnosis of phenylketonuria.
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Affiliation(s)
- Roman Kand'ár
- Department of Biological and Biochemical Sciences, Faculty of Chemical Technology, University of Pardubice, Strossova 239, 530 03 Pardubice, Czech Republic.
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Sánchez-Machado D, Chavira-Willys B, López-Cervantes J. High-performance liquid chromatography with fluorescence detection for quantitation of tryptophan and tyrosine in a shrimp waste protein concentrate. J Chromatogr B Analyt Technol Biomed Life Sci 2008; 863:88-93. [DOI: 10.1016/j.jchromb.2008.01.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2007] [Revised: 12/05/2007] [Accepted: 01/04/2008] [Indexed: 10/22/2022]
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31
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Blood phenylalanine monitoring for dietary compliance among patients with phenylketonuria: comparison of methods. Genet Med 2008; 9:761-5. [PMID: 18007145 DOI: 10.1097/gim.0b013e318159a355] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Blood phenylalanine monitoring is critical for the management of phenylketonuria. We compared three methods for measuring blood phenylalanine concentration: the amino acid analyzer, high-performance liquid chromatography with fluorometric detection, and tandem mass spectrometry. METHODS We studied 22 female patients with phenylketonuria, ages 12-48 years, who attended our Metabolic Camp. Blood was collected into heparinized tubes (for analysis by the amino acid analyzer) or filter paper (for analysis by high-performance liquid chromatography with fluorometric detection and tandem mass spectrometry). RESULTS Blood phenylalanine concentrations of plasma measured by the amino acid analyzer were significantly higher than those obtained from whole blood on filter paper by high-performance liquid chromatography (difference: 102 microM; 95% confidence interval: 23, 181) and tandem mass spectrometry (difference: 137 microM; 95% confidence interval: 58, 216). Phenylalanine concentrations from high-performance liquid chromatography and tandem mass spectrometry were not significantly different (P = 0.5). CONCLUSIONS When monitoring blood phenylalanine concentrations for dietary compliance, clinicians should be mindful of the method being used; analyses of whole blood on filter paper were consistently approximately 15% lower than analyses of plasma.
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Lin HC, Chou YH, Yang J. Development of an aminocarboxylic acid-modified infrared chemical sensor for selective determination of tyrosine in urine. Anal Chim Acta 2008; 606:230-8. [DOI: 10.1016/j.aca.2007.11.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Revised: 11/08/2007] [Accepted: 11/09/2007] [Indexed: 01/17/2023]
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Chen L, Woo SL. Correction in female PKU mice by repeated administration of mPAH cDNA using phiBT1 integration system. Mol Ther 2007; 15:1789-95. [PMID: 17637719 DOI: 10.1038/sj.mt.6300257] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Phenylketonuria (PKU) is a metabolic disorder secondary to a hepatic deficiency of phenylalanine hydroxylase (PAH) that predisposes affected children to develop severe and irreversible mental retardation. We have previously reported the complete and permanent correction of the hyperphenylalaninemic and hypopigmentation phenotypes in male, but not female, PKU mice after genome-targeted delivery of murine PAH (mPAH) complementary DNA (cDNA) in a phiBT1 bacteriophage integration system. Here we show that sequential administration of green fluorescent protein (GFP)- and red fluorescent protein (RFP)-expressing cassettes in the phiBT1 integration system led to distinct and non-overlapping populations of green and red fluorescent hepatocytes in vivo. The hyperphenylalaninemic and hypopigmentation phenotypes of female PKU mice were completely corrected after 10 weekly administrations of mPAH cDNA. Importantly, there was no apparent liver pathology in mice even after 10 consecutive administrations of the phiBT1 integration system. The results indicate that repeated administration of transgenes in the phiBT1 integration system can lead to their genome-targeted integration in a diverse population of hepatocytes and result in the elevation of transgene expression levels in a cumulative manner, which can be utilized to overcome insufficient transgene expression owing to low genome integration frequencies in a gene therapy paradigm for metabolic disorders.
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Affiliation(s)
- Li Chen
- Department of Gene and Cell Medicine, Mount Sinai School of Medicine, New York, New York 10029, USA
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Chen L, Thung SN, Woo SLC. Metabolic basis of sexual dimorphism in PKU mice after genome-targeted PAH gene therapy. Mol Ther 2007; 15:1079-85. [PMID: 17406346 DOI: 10.1038/sj.mt.6300137] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
We have previously reported a transgene delivery system based on phiBT1 bacteriophage integrase that results in targeted insertion of transgenes into mammalian genomes, and its use in the delivery of murine phenylalanine hydroxylase (PAH) complementary DNA (cDNA) into the hepatocytes of male phenylketonuria (PKU) mice, leading to a complete and permanent correction of their hyperphenylalaninemic phenotype. In this study, we report only partial phenotypic correction in female PKU mice, even though hepatic PAH activities in both sexes after gene treatment were similar. Daily injections of tetrahydrobiopterin (BH4), an essential co-factor for phenylalanine hydroxylation, in the gene-treated females led to complete correction of their PKU phenotype. After gonadectomy, serum phenylalanine levels in the gene-treated females were reduced to normal, whereas those in the gene-treated males remained unchanged. The sterile gene-treated PKU mice were subjected to daily sex hormone injections. Whereas the estradiol-treated sterile males developed hyperphenylalaninemia, the dihydrotestosterone-treated sterile females remained normal phenylalaninemic. The results indicate that it is estrogen that suppresses the steady-state levels of BH4 in mouse hepatocytes that became limiting, which is the underlying mechanism for the observed sexual dimorphism in PKU mice after PAH gene treatment. Livers of the PAH gene-corrected PKU mice also appeared normal and without apparent pathologies.
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Affiliation(s)
- Li Chen
- Department of Gene and Cell Medicine, Mount Sinai School of Medicine, New York, New York 10029, USA
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Korös A, Hanczkó R, Jámbor A, Qian Y, Perl A, Molnár-Perl I. Analysis of amino acids and biogenic amines in biological tissues as their o-phthalaldehyde/ethanethiol/fluorenylmethyl chloroformate derivatives by high-performance liquid chromatography. A deproteinization study. J Chromatogr A 2006; 1149:46-55. [PMID: 17145062 DOI: 10.1016/j.chroma.2006.11.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2006] [Revised: 11/02/2006] [Accepted: 11/07/2006] [Indexed: 11/28/2022]
Abstract
The extraction of ornithine, lysine, putrescine, cadaverine, 1,7-diaminoheptane, spermidine and spermine from biological tissues was optimized for HPLC quantitation as their o-phthalaldehyde/ethanethiol/fluorenylmethyl chloroformate (OPA/ET/FMOC) derivatives. In applying perchloric acid deproteinization two approaches have been followed: (i) deproteinization with subsequent neutralization by potassium hydroxide and lyophilization, and (ii) deproteinization without neutralization and lyophilization. Neutralization and lyophilization resulted in the loss of free biogenic amines. HPLC analysis of ornithine (Orn), lysine (Lys), putrescine (Put), cadaverine (Cad), 1,7-diaminoheptane (Dah), spermidine (Spd) and spermine (Spm) content of biological tissues as their OPA/ET/FMOC derivatives was performed in the supernatant of perchloric acid-deproteinized samples (model solutions and tissues) with an average reproducibility of < or =2.6% relative standard deviation (RSD), including recovery of sample treatment and chromatography.
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Affiliation(s)
- A Korös
- Institute of Chemistry, Department of Analytical Chemistry, L. Eötvös University, Budapest, Hungary
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Lee CJ, Yang J. alpha-Cyclodextrin-modified infrared chemical sensor for selective determination of tyrosine in biological fluids. Anal Biochem 2006; 359:124-31. [PMID: 17046708 DOI: 10.1016/j.ab.2006.09.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2006] [Accepted: 09/06/2006] [Indexed: 11/24/2022]
Abstract
In this paper, we propose an evanescent wave-based infrared (IR) spectroscopic sensing method for the selective and sensitive detection of tyrosine in aqueous solution. In this approach, alpha-cyclodextrin (alpha-CTD) was chemically immobilized onto the surface of an IR-sensing element to attract tyrosine specifically to the surface of the sensing element. Theoretical equations were developed for the quantitative analysis of tyrosine. Based on its IR spectra, the synthesized alpha-CTD phase was stable in water. Optimal detection with this system occurred when the pH of the solution was ca. 10.5. Based on the absorption bands, we confirmed that alpha-CTD was most effective at attracting tyrosine under basic conditions. Using the unique absorption band of tyrosine at 1500 cm(-1), the alpha-CTD phase allowed the detection of tyrosine selectively from among a range of potentially interfering amino acids and other species commonly present in biological samples. For quantitative analysis, this CTD-modified phase was most suitable for sensing tyrosine at concentrations below 100 microM because of limits in the surface adsorption mechanism. The detection times were, in some instances, lower than 5 min. For a detection time of 10 min, the detection limit of tyrosine was ca. 0.4 microM.
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Affiliation(s)
- Chung-Jay Lee
- Department of Chemistry, National Chung-Hsing University, Taichung 402, Taiwan
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Zhao G, Qi Y, Tian Y. Simultaneous and Direct Determination of Tryptophan and Tyrosine at Boron-Doped Diamond Electrode. ELECTROANAL 2006. [DOI: 10.1002/elan.200503455] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Chen L, Woo SLC. Complete and persistent phenotypic correction of phenylketonuria in mice by site-specific genome integration of murine phenylalanine hydroxylase cDNA. Proc Natl Acad Sci U S A 2005; 102:15581-6. [PMID: 16230623 PMCID: PMC1266087 DOI: 10.1073/pnas.0503877102] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We explored the potential of using a bacteriophage integrase system to achieve site-specific genome integration of murine phenylalanine hydroxylase cDNA in the livers of phenylketonuric (PKU) mice. The phiBT1 phage integrase is an enzyme that catalyses the efficient recombination between unique sequences in the phage and bacterial genomes, leading to the site-specific integration of the former into the latter in a unidirectional manner. Here we showed that this phage integrase functions efficiently in mouse cells, and several naturally occurring pseudo-attP sites located in the intergenic regions of the mouse genome have been identified and molecularly characterized. We further demonstrated that the addition of nuclear localization signal sequences to the C terminus of the phage integrase enhanced the efficiency for transgene integration into the mouse genome. Using this phage integration system, we delivered mouse phenylalanine hydroxylase cDNA to the livers of PKU mice by hydrodynamic injection of plasmid DNA and showed that the severity of the hyperphenylalaninemic phenotype in the treated mice decreased significantly. After three applications, serum phenylalanine levels in all treated PKU mice were reduced to the normal range and remained stable thereafter. Their fur color also changed from gray to black, indicating the reconstitution of melanin biosynthesis as a result of available tyrosine derived from reconstituted phenylalanine hydroxylation in the liver. Thus, the phiBT1 bacteriophage integrase represents an effective site-specific genome integration system in mammalian cells and can be of great value in DNA-mediated gene therapy for a multitude of genetic disorders.
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Affiliation(s)
- Li Chen
- Department of Gene and Cell Medicine, Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA
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McMahon AM, Doyle EM, O’Connor KE. Detection and quantification of 4-substituted phenols: a comparison of mushroom tyrosinase and cell extracts of Pseudomonas putida F6. Enzyme Microb Technol 2005. [DOI: 10.1016/j.enzmictec.2005.01.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Huang GG, Yang J. Development of infrared optical sensor for selective detection of tyrosine in biological fluids. Biosens Bioelectron 2004; 21:408-18. [PMID: 16076429 DOI: 10.1016/j.bios.2004.11.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2004] [Revised: 10/15/2004] [Accepted: 11/02/2004] [Indexed: 01/13/2023]
Abstract
In this paper, a new and simple evanescent wave type of infrared biosensor is described for the selective detection of tyrosine in biological fluids. This sensor is based on the formation of copper complexes between the sensing phase and tyrosine. To demonstrate that this principle was applicable to the selective detection of tyrosine, a proline-modified sensing phase was synthesized on the surface of the internal reflection elements. This sensing phase was saturated with copper ions to allow it to interact with tyrosine units in aqueous solution through the formation of stable proline-Cu2+-tyrosine complexes. Tyrosine exhibits a unique spectral feature in its absorption band at 1515 cm-1. This band significantly differs from those of other amino acids and provides a further method for the discrimination of tyrosine. By investigating the signals from 12 amino acids, only three amino acids, each containing a phenyl group, could be sensed selectively by this sensing phase. Based on the unique absorption of tyrosine located at 1515 cm-1, tyrosine can be selectively detected. To perform quantitative analyses of tyrosine using this sensing phase, a theoretical working equation was developed and correlated with the experimental data. The analytical results indicated that the developed equations do explain and predict the detection behaviors of the proposed sensing scheme. Using the optimal conditions, the regression coefficients for standard curves of tyrosine recorded in the region of concentrations below 600 microM were higher than 0.996 under either equilibrium or non-equilibrium conditions. Detection limit of tyrosine when using this method was ca. 3 microM.
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Affiliation(s)
- Genin Gary Huang
- Department of Chemistry, National Chung-Hsing University, Taichung 402, Taiwan
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Wibrand F. A microplate-based enzymatic assay for the simultaneous determination of phenylalanine and tyrosine in serum. Clin Chim Acta 2004; 347:89-96. [PMID: 15313145 DOI: 10.1016/j.cccn.2004.04.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2004] [Revised: 04/01/2004] [Accepted: 04/05/2004] [Indexed: 11/24/2022]
Abstract
BACKGROUND Several methods have been reported for the quantitation of phenylalanine (Phe) or tyrosine (Tyr) in blood, but the simultaneous determination of Phe and Tyr usually requires sophisticated equipment. Here we describe a simple and reliable microplate assay for measurement of Phe and Tyr in serum of patients with phenylketonuria (PKU). METHODS Serum was deproteinised and incubated with phenylalanine ammonia-lyase at 37 degrees C for 2 h. Phe and Tyr were converted to trans-cinnamate and trans-coumarate, respectively, which were determined UV spectrophotometrically. RESULTS The assay demonstrated linearity up to 3200 micromol/l Phe and 640 micromol/l Tyr. The sensitivity of the assay was 15 micromol/l for Phe and 5 micromol/l for Tyr. Analytical recovery was 105% and 97% for Phe and Tyr, respectively. The between-run coefficient of variation (CV) varied with concentration but was 4.7-18.8% for Phe and 4.2-8.8% for Tyr. The within-run CV was 2.7% for Phe and 6.5% for Tyr. Results obtained with the assay correlated well with those of an ion exchange chromatographic method. CONCLUSIONS This novel assay is sensitive, accurate, precise and suitable for routine monitoring of PKU patients.
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Affiliation(s)
- Flemming Wibrand
- John F. Kennedy Institute, Gl. Landevej 7, 2600 Glostrup, Denmark.
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N/A. N/A. Shijie Huaren Xiaohua Zazhi 2004; 12:1210-1213. [DOI: 10.11569/wcjd.v12.i5.1210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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