THE PURIFICATION AND CHARACTERIZATION OF PROLYL AMINOPEPTIDASE FROM PENICILLIUM-CAMEMBERTI

Prolyl aminopeptidase [EC 3.4.11.5] from the cell-free extract of Peni cillium camemberti was purified about 2800-fold by chromatographic tec hniques. The purity of the enzyme was confirmed by electrophoretic ana lysis. The molecular mass of the enzyme was estimated to be 270,000 Da by gel filtration. The enzyme had a maximum activity at pH 7.0 and 45 -degrees-C, and Pro-p-naphthylamide was the substrate; the enzyme was stable up to 50-degrees-C. The enzyme cleaved Pro-amino acid bond when the Pro residue was at the amino-terminal. The enzyme was completely inactivated by p-chloromercuribenzoic acid and reduced to approximatel y 50% activity by diisopropyl fluorophosphate. The Michaelis-Menten co nstant was estimated to be .25 mM and the maximum velocity to be .56 m M/min per ml.