Studies on human urinary arylamidases

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 pH optima for the hydrolysis of the various naphthylamides were also determined. Glycyl-prolyl-arylaminade was inhibited by Co(2+) and Mn(2+), while two other arylamidases were slightly activated by Co(2+). p-Chloromercuriphenyl-sulfonate and puromycin significantly inhibited leucyl and alanyl arylamidases. The mean values for 24-hour urinary output for leucyl-, alanyl-, and glycyl-prolyl arylamidases in normal human male subjects were 4.32, 9.97, and 2.2 units, respectively.