KINETIC-ANALYSIS OF PAPAYA PROTEINASE-OMEGA

Papaya proteinase OMEGA (ppOMEGA) has been purified from dried latex b oth by immunoaffinity and traditional methods. Kinetic analysis reveal ed that (1), the ppOMEGA-catalysed hydrolysis of N-benzoyl-L-arginine p-nitroanilide (BApNA) has a lower specificity (k(cat)/K(m)) than the same reaction catalysed by papain; (2), the ppOMEGA-catalysed hydrolys is of a tripeptide substrate having phenylalanine at the second positi on (S2-site) showed a more similar specificity to that catalysed by pa pain; (3), the significant difference between the two enzymes is that steady state kinetics with both L-BApNA and a tripeptide enables the i dentification in ppOMEGA of other ionizations affecting binding. The a ctive sites of papain and ppOMEGA can therefore be distinguished by pH -dependence of k(cat)/K(m).