title: An optimized assay of alanine aminopeptidase activity in urine.
abstract: Elaboration of an optimized kinetic test for urinary alanine aminopeptidase at 37 degrees C is described. As final concentrations, 50 mmol/L tris(hydroxymethyl)aminomethane x HCl buffer, pH 7.8, and 2 mmol/L alanine-4-nitroanilide are proposed. Five- to sixfold activitiy is obtained as compared with a generally used test procedure. Coefficients of variation for the method (within-run and between-day precision) ranged from 1.56 to 3.45%. Men excreted more alanine aminopeptidase than did women if urinary volume or urinary timed volume was used as basis of reference. We saw no sex-related differences in excretion of alanine aminopeptidase when enzyme excretion was related to urinary creatinine.
mesh_terms: D000328:Adult; D000626:Aminopeptidases / Q000652:urine*; D001322:Autoanalysis; D018826:CD13 Antigens; D004796:Clinical Enzyme Tests; D005260:Female; D006801:Humans; D007202:Indicators and Reagents; D007674:Kidney Diseases / Q000175:diagnosis; D016030:Kidney Transplantation; D007700:Kinetics; D008297:Male; D012016:Reference Values; D014184:Transplantation, Homologous
chemical_list: D007202:Indicators and Reagents; D000626:Aminopeptidases; D018826:CD13 Antigens