title: Studies on human urinary arylamidases.
abstract: Human urinary protein was found to contain enzymes that hydrolyze leucyl-, alanyl-, and glycyl-prolyl-beta-naphthylamides. The kinetic constants of these enzymes were determined and their chemical properties studied. The values for Km calculated for leucyl-, alanyl-, and glycyl-prolyl arylamidases were 3.7 times 10(-5) M, 7.1 times 10(-5) M, and 1 times 10(-4) M, respectively. The pH optima for the hydrolysis of Leu-beta-naphthylamide and Ala-beta-naphthylamide were between 7.4-7.8; whereas for glycyl-prolyl-beta-naphthylamide, it was around 8.8. Unlike the glycyl-prolyl-arylamidase which was inhibited by Co2+ and Mn2+, the other two arylamidases were slightly activated by Co2+. p-Chloromercuriphenyl-sulfonate and puromycin significantly inhibited leucyl-, and alanyl arylamidases. The mean values for 24-h urinary output for leucyl-, alanyl-, and glycyl-prolyl arylamidases in normal human male subjects were 4.32, 9.97, and 2.2 units, respectively.
mesh_terms: D000293:Adolescent; D000328:Adult; D000626:Aminopeptidases / Q000037:antagonists & inhibitors / Q000652:urine*; D002614:Chelating Agents / Q000494:pharmacology; D004789:Enzyme Activation; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007931:Leucyl Aminopeptidase / Q000037:antagonists & inhibitors / Q000652:urine; D008297:Male; D013329:Structure-Activity Relationship; D013438:Sulfhydryl Compounds / Q000494:pharmacology; D014131:Trace Elements / Q000494:pharmacology
chemical_list: D002614:Chelating Agents; D013438:Sulfhydryl Compounds; D014131:Trace Elements; D000626:Aminopeptidases; D007931:Leucyl Aminopeptidase