Detection of S-1-P-1 and S-3-P-3 interactions between papain and four synthetic substrates

In this study, the S-1-P-1 and S-3-P-3 interactions between papain and four synthetic peptide substrates were found as to be important, The values of K-m were estimated as to be practically identical between these substrates; this latter is supporting the conclusions obtained by considering the esti mated values of other kinetic parameters. Nevertheless, based on the estima ted k(cat) and/or k(cat)/K-m parameters of the used substrates, we conclude d that an aromatic ring at the P-3 position, and a positively charged side chain of the residue at the P-1 position of the synthetic substrates were f avored considerably their interaction with papain.