PEPTIDASES IN SKIN .2. DEMONSTRATION AND PARTIAL SEPARATION OF SEVERAL SPECIFIC DIPEPTIDE NAPHTHYLAMIDASES IN RAT AND HUMAN SKIN

Rat and human skin homogenate were fractionated using gel filtration of Sephadex G-100, and several enzymes hydrolysing dipeptide naphthylamides were partially separated. The presence of the following enzymes was demonstrated: 1. an enzyme hydrolysing glycyl-proline naphthylamide optimally at pH 7.6-7.8, corresponding to a similar enzyme found in the rat liver, 2. an enzyme hydrolysing lysyl-alanine naphthylamide optimally at pH 5.3-5.5, corresponding to the so-called dipeptidyl arylamidase II of bovine pituitary, 3. an sulfhydryl-dependent enzyme hydrolysing arginyl-arginine naphthylamide optimally at pH 8.0, corresponding to the so-called dipeptidyl arylamidase III of bovine pituitary, 4. a sulfhydryl-dependent enzyme hydrolysing alanyl-alanine naphthylamide optimally at pH 5.0, corresponding to cathepsin C. This enzyme was found to be present in the human skin only. In addition, aminopeptidase B, earlier demonstrated in the rat skin, was found to be present in the human skin. © 1969 Springer-Verlag.