[A membrane-bound alanine aminopeptidase from Acinetobacter calcoaceticus. 1. Isolation and purification of the enzyme].

The alanine aminopeptidase of Acinetobacter calcoaceticus was found to be bound to the inner membranes only. The enzyme was solubilized by Triton X-100 and purified approximately 480-fold by gel filtration and affinity chromatography on alanine methyl ketone-AH-Sepharose 4B. The purified alanine aminopeptidase has a molecular mass of 212 kDa, estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme selectively catalyses the hydrolysis of N-terminal alanine residues of peptides. The enzyme is inhibited by p-hydroxy-mercuribenzoate, 1,10-phenanthroline, and puromycin, but was activated by CO2(+)-ions.