Collect. Czech. Chem. Commun. 1988, 53, 2884-2889

Specific water-soluble substrates for chymotrypsin: Attempts for compensating diminished P1-S1 interactions

Volker Schellenberger, Ute Schellenberger and Hans-Dieter Jakubke

Karl-Marx-University, Biosciences Division, Department of Biochemistry, DDR - 7010 Leipzig, G.D.R.


N-Maleyl-L-amino acid and peptide esters were synthesized and employed as substrates for α-chymotrypsin. From the kcat/KM values can be suggested that benzyl esters are significantly better substrates than the appropriate methyl esters. Further improvement in the substrate properties results from the introduction of the p-nitrobenzyl ester moiety. The choline ester of benzyloxycarbonyl-L-phenylalanine with the highest kcat/KM value confirmed the P1' leaving group specificity for positively charged residues. From the kinetic data can be concluded that acyl donors with high kcat/KM values, which are useful in kinetically controlled enzymatic peptide synthesis, need not contain aromatic amino acid residues in the P1 position.