Feedback Inhibition of Porcine Muscle Alanyl and Arginyl Aminopeptidases in Cured Meat Products

Abstract

Alanyl and arginyl aminopeptidases from porcine skeletal muscle were purified, and the effect of free amino acids on their activities was studied. Both aminopeptidases were inhibited by free amino acids via the competitive mode and were more strongly inhibited in the pure form than when they were in the meat extract. Arginyl aminopeptidase (RAP)was less susceptible to inhibition by free amino acids than alanyl aminopeptidase (AAP), as shown especially by the strong inhibitory effect of hydrophobic amino acids on AAP activity in the meat extract. The free amino acid concentration present in meat products such as dry-cured loin and dry-cured ham produced a strong inhibitory effect on AAP and RAP activity. The concentration of free amino acids in cooked ham mainly affected the activity of AAP. These facts can explain the differences obtained in free amino acid concentration depending on the kind of process or product. Keywords: Aminopeptidase; muscle exopeptidases; peptidase inhibitor; amino acid