PEPTIDASES IN SKIN .I. BIOCHEMICAL DEMONSTRATION OF AN AMINOPEPTIDASE IN RAT SKIN SPECIFIC FOR N-TERMINAL BASIC AMINO ACIDS (AMINOPEPTIDASE B)

Rat skin homogenate was fractionated using gel filtration on Sephadex G-100, and several enzymes hydrolysing aminoacid naphthylamides were partially separated. One of the enzymes was found to hydrolyse naphthylamides of arginine and lysine but not of the twelve other aminoacids tested, e.g. leucine naphthylamide. The enzymic hydrolysis of arginine naphthylamide was optimal at neutral pH and was markedly enhanced by chloride ions at a concentration of 0.2 M. Methanol and sulfhydryl reagents were effective inhibitors while EDTA and DFP had no effect. This enzyme is similar to aminopeptidase B, an enzyme described earlier in several other mammalian tissues. © 1968 Springer-Verlag.