Muscle Arylamidase Activity of Several Marine Species

Abstract

Arylamidase activity in muscle extracts of mackerel, mullet, whiting, blue crab, quahog clam, and shrimp was investigated. The optimum pH for activity was between 7.0 and 7.5 for each species using alanyl-β-naphthylamide as substrate. Enzymes of the three species of fish exhibited maximum activity against alanyl-β-naphthylamide, whereas the clam showed maximum activity with leucyl-β-naphthylamide and the crab and shrimp with lysyl-β-naphthylamide. Puromycin inhibited each of the arylamidases. Acrylamide gel electrophoresis of the crude extracts suggested the presence of one arylamidase in muscle of the fish, crab, and clam. The shrimp muscle extract contained two active enzymes. Upon electrophoresis, the faster moving enzyme from shrimp muscle was active against lysyl-, alanyl-, and leucyl-β-naphthylamides, but the slower moving enzyme was active only against lysyl-β-naphthylamide.