Feedback inhibition of porcine muscle alanyl and arginyl aminopeptidases in cured meat products

Alanyl and arginyl aminopeptidases from porcine skeletal muscle were purifi ed, and the effect of free amino acids on their activities was studied. Bot h aminopeptidases were inhibited by free amino acids via the competitive mo de and were more strongly inhibited in the pure form than when they were in the meat extract. Arginyl aminopeptidase (RAP)was less susceptible to inhi bition by free amino acids than alanyl aminopeptidase (AAP), as shown espec ially by the strong inhibitory effect of hydrophobic amino acids on AAP act ivity in the meat extract. The free amino acid concentration present in mea t products such as dry-cured loin and dry-cured ham produced a strong inhib itory 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.