Tryptic hydrolysis of omega-amidino alpha-amino acid (indospecine) esters

Several esters of a series of omega-amidino alpha-amino acids were synthesized. Some of them were shown to be efficiently hydrolyzed by bovine trypsin [EC 3.4.21.4]. The kinetics of hydrolysis of the esters were compared with those of the omega-guanidino series. The relationships between the length of the side chain and the susceptibility to hydrolysis by trypsin were somewhat different in the two series. These slight differences are discussed in terms of the molecular structures and their relation to the structural requirements of the trypsin active site.