The Purification and Characterization of Prolyl Aminopeptidase from Penicillium camemberti

Abstract

Prolyl aminopeptidase [EC 3.4. 11.5] from the cell-free extract of Penicillium camemberti was purified about 2800-fold by chromatographic techniques. The purity of the enzyme was confirmed by electrophoretic analysis. 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°C, and Pro-p-naphthylamide was the substrate; the enzyme was stable up to 50°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 approximately 50% activity by diisopropyl fluorophosphate. The Michaelis-Menten constant was estimated to be .25mM and the maximum velocity to be .56mM/min per ml.