Analysis of interactions of protease inhibitors with proteases in a high-throughput format.

A collection of protease inhibitors was screened forthe interaction with various serine (trypsin, cathepsin B) and cysteine (papain, ficin, bromelain) proteases possessing cleavage activity towards a Dabcyl pentapeptide fluorogenic substrate. Protease inhibitor's instability (constant of protease-inhibitor complex) was determined prior to their use in the arrayed format. The inhibitors used were: St-CYST, A. thaliana cysteien protease inhibitor); MTI2, mustard trypsin inhibitor; MTI-2-AAA mutant without inhibitory activity; MTI-2-PLI mustard chymotrypsin inhibitor; MTI-2-PAI trypsin inhibitor; Chymo8, chymotrypsin inhibitor; RTI-2, rapeseed glutamyl protease inhibitor;Silk protease inhibitors (six variants with one modified amino acid in the P1 site: thr, Trp, Ala, His, Met, Asp, with various efficiencies in inhibiting elastase, proteinase K, thermolysin and tryspin; Sb-RI, soybean trypsin inhibitor. Inhibitors were spotted onto Schleicher-Schuell nitrocelulose slides, and proteases were labelled with cyanine-3 before hybridisation with slides. Data presented show the specificity of binding to each inhibitor and on activity of proteases.