Studies on acceleration of Ras cheese ripening by aminopeptidases enzyme from buffaloes' pancreas. I. purification and characterization of buffaloes pancreas aminopeptidas

Aminopeptidaes [EC. 3.4.11.1] was purified from fresh buffaloes pancreas by ammonium sulfate fractionation at 30-40% saturation [w/v], followed by gel filtration chromatography on sephadex G-l 00 column about 9.6 fold with 20% recovery of crude extract. The enzyme had a molecular weight [MW] about 20 kDa by gel filtration chromatography on sephadex G 100 column. The purified enzyme exhibited maximum activity on leucine-p-nitroanilide pH 6.0 and 40°C. The enzyme was strongly activated by 1 mM of Ca [+2], Na[+], respectively, but strongly inhibited by 1 mM of Cu[+]2 and Cd[+]2. The purified aminopeptidase activity was not significantly affected by I mM of EDTA and 1, 10 Phenanthroline