Serine proteinase inhibitor from wax gourd (Benincasa hispida [Thunb] Cogn.) seeds.

Two squash family protease inhibitors were obtained from wax gourd (Benicasa hispida [Thunb] Cogn.). Even though they were distinctly separated by reversed-phase chromatography, the amino acid sequences of two inhibitors were identical. Both inhibitors were converted into each other, perhaps due to cis-trans isomerization of characteristic Pro in the C-terminal region.