Cereal Chem 58:194 - 198.  |  VIEW ARTICLE
Trypsin Inhibitor from Rye Endosperm: Purification and Properties.

S. Boisen and R. Djurtoft. Copyright 1981 by the American Association of Cereal Chemists, Inc. 

A trypsin inhibitor was isolated from the endosperm of rye seeds by extraction with a 0.1M sodium acetate buffer (pH 4.9), fractionation with ammonium sulfate, heat treatment, ion-exchange chromatography on SP- Sephadex C-50, and gel filtration on Ultrogel AcA 54. The final preparation was homogeneous by electrophoretic analyses. The inhibitor was a protein with a molecular weight of about 12,500 and an isoelectric point of about 9.0. The amino acid composition differed from that of a trypsin inhibitor previously isolated from rye embryo. The action of the endosperm inhibitor on bovine trypsin was linear up to 90% inhibition with benzoyl-l-arginine-p-nitroanilide as substrate and up to 80% with casein as substrate. The preparation had a weak, nonstoichiometric inhibitor action on bovine chymotrypsin but no activity on porcine elastase. The inhibitor was heat-stable at 100 C, and up to 15% of the original activity could still be extracted from different rye bread types. Immunochemical studies with specific antibodies indicated that the inhibitor may have been modified during the baking process.