Purification and Characterization of L-Phenylalanine Aminopeptidase from Chick-Pea Cotyledons (Cicer arietinum L.)

Chick-pea (Cicer arietinum L.) cotyledons are unique source of aminopeptidase - 8-9 U/g cotyledons was observed using L-leucine-p-nitroanilide as substrate. The aminopeptidase was purified (65 kDa, pI 4.8 ) reaching a specific activity of 220 U/mg at pH 7.0-7.2 and 35-40°C. The determined constant of specificity kcat/Km during hydrolysis of Nunsubstituted amino acid-p-nitroanilides showed a decrease order: Phe>Leu>Pro>Ile>Val>Ala. The enzyme was strongly inhibited by p-chloromercuribenzoic acid as well as in a competitive rate by the antihypertensive peptides Ile-Pro-Pro and Val-Pro-Pro.