Arylamidases in normal and diseased human muscle.

Human skeletal muscle homogenates were found to contain enzymes that catalyze the hydrolysis of beta-naphthylamides of leucine, arginine and lysine, known substrates for neutral and basic arylamidases. They also contained a trace of activity towards alpha-aspartyl-beta-naphthylamide. The muscle arylamidases were found to be inhibited by p-chloromercuribenzoate, Hg2+ and puromycin. Leucyl, arginyl and lysysl arylamidases were slightly activated by cobalt ions. When compared to controls, no significant differences in muscle arylamidase activities were observed in patients with muscular dystrophies and certain denervating diseases.