Purification and Some Properties of Trypsin Inhibitors from Buckwheat Seeds

Abstract

Seven proteins which inhibited trypsin were purified from buckwheat seeds by (NH₄)₂SO₄ fractionation, gel-filtration, and DEAE- and CM-cellulose column chromatographies. The homogeneities of the purified inhibitors were established by polyacrylamide gel electrophoresis. These inhibitors were thermostable at acidic and neutral pH’s and acted on trypsin more powerfully than on chymotrypsin. Three of them, BTI He, Illbl, and IIIb2, were typical temporary inhibitors of trypsin and the others, BTI I, Ha, lib, and Ilia, were permanent ones. These seven inhibitors had essentially no inhibitory activity against subtilisin, Aspergillus sydowi proteinase, neutral sub-tilopeptidase, papain, or pepsin.