Amino acid- -naphthylamide hydrolysis by Pseudomonas aeruginosa arylamidase

The intracellular and constitutive arylamidase from Pseudomonas aeruginosa was purified 528-fold by salt fractionation, ion-exchange chromatography, gel filtration, and adsorption chromatography. This enzyme hydrolyzed basic and neutral N-terminal amino acid residues from amino-beta-naphthylamides, dipeptide-beta-naphthylamides, and a variety of polypeptides. Only those substrates having an l-amino acid with an unsubstituted alpha-amino group as the N-terminal residue were susceptible to enzymatic hydrolysis. The molecular weight was estimated to be 71,000 daltons. The lowest K(m) values were associated with substrates having neutral or basic amino acid residues with large side chains with no substitution or branching on the beta carbon atom.