ARYLAMIDASE OF HUMAN LIVER

1. 1. Arylamidase from human liver, which catalyzes the hydrolysis of certain amino acid derivatives of β-naphthylamine, was purified 2120-fold by salt fractionation, gel filtration, ion-exchange chromatography, and adsorption chromatography. 2. 2. Acrylamide gel electrophoresis and analytical ultracentrifugation of the final enzyme preparation indicated that it was a single protein with a s20,w value of 8.5. 3. 3. Only α-amino acid β-naphthylamines of the l configuration were susceptible to arylamide catalyzed hydrolysis; alanine-β-naphthylamine had the highest max value. Several other substrates in which the amino acid residue had a larger non-polar or basic R group such as methionine-β-naphthylamine or arginine-β-naphthylamine had the lower Km values. 4. 4. This enzyme had no dipeptidyl arylamidase activity, but rather cleaved amino acid residues from dipeptide-β-naphthylamine in a step-wise manner beginning with the N-terminal residue. © 1969.