Arylamidase of Cephalosporium acremonium and Its Specificity for Cephalosporin C

Abstract

Three aggregational forms of arylamidase are produced by Cephalosporium acremonium. The exocellular enzyme, with an approximate molecular weight of 60,000, was purified 300-fold by diethylaminoethyl cellulose chromatography, gel filtration, and gel electrophoresis. With l-leucyl-β-naphthylamide as the substrate, the Km is 4.2 × 10−4m; the optimum pH, 7.7; and the temperature optimum, 35 C. The enzymatic hydrolysis of l-leucyl-β-naphthylamide is inhibited by a number of cephalosporins, whereas a variety of penicillins show no effect. Alternatively, the enzyme specifically catalyzes the β-lactam hydrolysis of a number of cephalosporins; a number of penicillins are resistant. The Km for cephalosporin C is 9.09 × 10−4m.