Alkylamidase of sheep liver

Abstract

1. 1. An amidase from sheep liver microsomes which catalyzes the hydrolysis of N-monosubstituted and N,N-disubstituted amides was purified 59-fold by hydroxylapatite and benzyl-DEAE-cellulose column chromatography. 2. 2. Acrylamide gel electrophoresis of the final enzyme preparation indicated that it was a single protein. 3. 3. The enzyme had an optimum at approximately pH 9, was not stimulated by divalent cations and had a molecular weight, as determined by gel filtration, of 230 000 to 250 000. 4. 4. The enzyme was unable to hydrolyze the lower members of a series of N- methyl-substituted amides and only had a trace of activity to N- methyl butyramide. The activity reached a maximum with N- methyl caproamide and decreased with an increase in chain length. The enzyme hydrolyzed N- methyl, N- ethyl and N- propyl caproamide at approximately equal rates. Of all the compounds investigated as substrates. N- phenyl caproamide had the shortest enzymatic half-life. Of the N,N- dialkyl-substituted caproamides evaluated, only N,N- dimethyl caproamide was hydrolyzed.