Inhibitory activities of partially degraded salivary cystatins

1. Aminoterminally truncated forms of cystatin S and cystatin SN had higher inhibition constants for ficin, but lower ones for cathepsin C (dipeptidyl peptidase I) as compared to their respective full-sized form. 2. Cystatin SN still retained the inhibitory activity for ficin after reduction and carboxymethylation, although the inhibition constant increased.