Amino acid substitution in an amidase produced by an acetanilide-utilizing mutant of Pseudomonas aeruginosa.

Mutants of Pseudomonas aeruginosa were isolated which grew with acetanilide (N-phenylacetamide) as the sole carbon source for growth. The mutants could also use acetanilide as a nitrogen source but grew better in the presence of ammonium salts. The acetanilide-utilizing mutants produced amidases which differed in substrate specificity and electrophoretic mobility from the wild-type A amidase and the B amidase produced by a butyramide-utilizing mutant. The amidase from one of the acetanilide-utilizing mutants was purified and shown to differ from the wild-type enzyme by the substitution of an isoleucine for a threonine residue.