Fluorometric and time-resolved immunofluorometric assays for protein-tyrosine phosphatase activity. 1996

B Galvan, and T K Christopoulos
Department of Chemistry and Biochemistry, University of Windsor, Ontario, Canada.

OBJECTIVE To develop sensitive nonisotopic assays for protein-tyrosine phosphatase (PTP) activity. METHODS The fluorometric assay is based on the fact that phosphotyrosine but not tyrosine forms highly fluorescent complexes with Tb3+. Thus, PTP activity can be followed by measuring the decrease of fluorescence due to hydrolysis of phosphotyrosine. The time-resolved immunofluorometric assay employs tyrosine-phosphorylated substrates, immobilized on microtitre wells. After incubation with PTP, the remaining phosphotyrosine residues are reacted with an antiphosphotyrosine antibody. The immunocomplexes formed are detected with an alkaline phosphatase (ALP)-labeled second antibody. The phosphate ester of 5' fluorosalicylate (FSAP) is used as substrate. The fluorosalicylate produced forms highly fluorescent complexes with Tb3+ - EDTA in alkaline solution. The fluorescence is measured with a time-resolved fluorometer. RESULTS The truncated form of the T-cell protein tyrosine phosphatase (TCdeltaC11 PTP) was determined in the range 1100-36,500 U/L by the fluorometric assay and 36-7100 U/L by the time-resolved immunofluorometric assay. CONCLUSIONS The two nonisotopic assays should prove beneficial for the determination and study of various PTP.

UI MeSH Term Description Entries
D005069 Evaluation Studies as Topic Works about studies that determine the effectiveness or value of processes, personnel, and equipment, or the material on conducting such studies. Critique,Evaluation Indexes,Evaluation Methodology,Evaluation Report,Evaluation Research,Methodology, Evaluation,Pre-Post Tests,Qualitative Evaluation,Quantitative Evaluation,Theoretical Effectiveness,Use-Effectiveness,Critiques,Effectiveness, Theoretical,Evaluation Methodologies,Evaluation Reports,Evaluation, Qualitative,Evaluation, Quantitative,Evaluations, Qualitative,Evaluations, Quantitative,Indexes, Evaluation,Methodologies, Evaluation,Pre Post Tests,Pre-Post Test,Qualitative Evaluations,Quantitative Evaluations,Report, Evaluation,Reports, Evaluation,Research, Evaluation,Test, Pre-Post,Tests, Pre-Post,Use Effectiveness
D005470 Fluorometry An analytical method for detecting and measuring FLUORESCENCE in compounds or targets such as cells, proteins, or nucleotides, or targets previously labeled with FLUORESCENCE AGENTS. Fluorimetry,Fluorometric Analysis,Analysis, Fluorometric
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006863 Hydrogen-Ion Concentration The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D012680 Sensitivity and Specificity Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed) Specificity,Sensitivity,Specificity and Sensitivity
D013601 T-Lymphocytes Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER). They are formed when lymphocytes circulate through the THYMUS GLAND and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen. T Cell,T Lymphocyte,T-Cells,Thymus-Dependent Lymphocytes,Cell, T,Cells, T,Lymphocyte, T,Lymphocyte, Thymus-Dependent,Lymphocytes, T,Lymphocytes, Thymus-Dependent,T Cells,T Lymphocytes,T-Cell,T-Lymphocyte,Thymus Dependent Lymphocytes,Thymus-Dependent Lymphocyte
D013997 Time Factors Elements of limited time intervals, contributing to particular results or situations. Time Series,Factor, Time,Time Factor
D015200 Fluoroimmunoassay The use of fluorescence spectrometry to obtain quantitative results for the FLUORESCENT ANTIBODY TECHNIQUE. One advantage over the other methods (e.g., radioimmunoassay) is its extreme sensitivity, with a detection limit on the order of tenths of microgram/liter. Immunofluorometric Assay,Time-Resolved Immunofluorometric Assay,Assay, Immunofluorometric,Assay, Time-Resolved Immunofluorometric,Assays, Immunofluorometric,Assays, Time-Resolved Immunofluorometric,Fluoroimmunoassays,Immunofluorometric Assay, Time-Resolved,Immunofluorometric Assays,Immunofluorometric Assays, Time-Resolved,Time Resolved Immunofluorometric Assay,Time-Resolved Immunofluorometric Assays
D017027 Protein Tyrosine Phosphatases An enzyme group that specifically dephosphorylates phosphotyrosyl residues in selected proteins. Together with PROTEIN-TYROSINE KINASE, it regulates tyrosine phosphorylation and dephosphorylation in cellular signal transduction and may play a role in cell growth control and carcinogenesis. Phosphotyrosine Phosphatase,Protein-Tyrosine-Phosphatase,Tyrosyl Phosphoprotein Phosphatase,PTPase,Phosphotyrosyl Protein Phosphatase,Protein-Tyrosine Phosphatase,Phosphatase, Phosphotyrosine,Phosphatase, Phosphotyrosyl Protein,Phosphatase, Protein-Tyrosine,Phosphatase, Tyrosyl Phosphoprotein,Phosphatases, Protein Tyrosine,Phosphoprotein Phosphatase, Tyrosyl,Protein Phosphatase, Phosphotyrosyl,Protein Tyrosine Phosphatase,Tyrosine Phosphatases, Protein

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