First report on a potato I family chymotrypsin inhibitor from the seeds of a Cucurbitaceous plant, Momordica cochinchinensis.

A 7514-Da chymotrypsin inhibitor was isolated from the seed extract of Momordica cochinchinensis (Family Cucurbitaceae) by chromatography on chymotrypsin-Sepharose 4B and subsequently by C18 reversed-phase HPLC. This inhibitor, named MCoCl, possessed remarkable thermostability and was stable from pH 2 to 12. MCoCl also inhibited subtilisin, but had at least 50-fold lower inhibitory activity towards trypsin and elastase.