Zymogen activation as a sensitive enzyme-amplifying assay for a protease with tryptic specificity.

A protease, ;trypsinogenase', secreted in small amounts by the sea-urchin blastula, is assayed in two steps as an example of enzyme-amplifying kinetics. In reaction 1 the trypsinogenase catalyses the activation of trypsinogen to trypsin. In reaction 2 the trypsin catalyses the hydrolysis of N-alpha-toluene-p-sulphonylarginine methyl ester, at a rate that is linear with trypsinogenase concentration over a 20-fold range. Results are reproducible within a batch of zymogen, but each batch requires a separate standard curve.