Proteolytic processing of penicillin amidase from Alcaligenes faecalis cloned in E-coli yields several active forms

Of four enzymatically active forms of Alcaligenes faecalis penicillin amida se (EC 3.5.1.11) observed in sonicated cells, two (PA(5.5) and PA(5.3); sub script denotes pI) could be isolated and purified in two steps from the cel ls destroyed by osmotic shock. Active enzyme was only found in the periplas m. PA(5.5) converts further to PA(5.3) which differs in the molecular mass of the A-chain. The origin of these differences is a conversion of the N-te rminal Gln to pyrolidenocarboxilic acid and a loss of three amino acids fro m the C-terminus of the A-chain. PA(5.3) had higher specific activity (10-3 0%) for the hydrolysis of benzylpenicillin and 6-nitro-3-phenylacetamidoben zoic acid than PA(5.5).