Biological effects of isolated trypsin inhibitor from winged bean (Psophocarpus tetragonolobus) on rats

Effects of heat treatments of antinutritional factors and quality of proteins in winged bean

“…It has recently been shown that combined and possibly synergistic effects of all these factors are responsible for the toxicity of raw winged bean. 7 Heat treatment is usual before legumes are used in the human diet. This improves protein quality by inactivating antiphysiological factors, particularly trypsin inhibitor and haemagglutinin, and by unfolding the protein structure, thus making them more susceptible to attack by digestive enzymes8 Earlier ~t u d i e s~.~ have shown that trypsin inhibitors and haemagglutinins in beans can be destroyed by moist heat treatment.…”

Detection of protease activities using specific aminoacyl or peptidyl p ‐nitroanilides after sodium dodecyl sulfate — polyacrylamide gel electrophoresis and its applications

“…The activity staining of trypsin inhibitors showed a clear zone against a magenta background. Although APNE was frequently used as a substrate for trypsin inhibitor activity staining [21,29], BANA seemed more suitable than APNE concerning far as substrate specificity.…”

“…This is regrettable because protease activity staining on gels may provide qualitative evidence of the existence of partially purified or purified protease(s) [20]. Chan and deLumen [21] developed a staining method for detecting trypsin inhibitor activity on polyacrylamide gels using N-acetyl-DL-phenylalanine b-naphthyl ester (APNE) as a trypsin substrate. However, APNE can not be used as a specific substrate in a quantitative spectrophotometric assay of trypsin.…”

Activity staining on polyacrylamide gels of trypsin inhibitors from leaves of sweet potato (Ipomoea batatas L. Lam) varieties

“…The procedure of Chan and deLumen [8] for activity staining of TIs on gels was modified as followed. When SDS-PAGE was finished, gels were cut into two parts.…”

“…Although TI activity staining is successful on gels for samples from the roots of sweet potatoes, inconsistent results were obtained for samples from the leaves of sweet potatoes (our unpublished data). Wang and Yeh [12] have reported the successful staining of TIs from the leaves of sweet potato varieties with a method modified from that of Chan and deLumen [8]. However, they failed to reproduce the previous results using another batch of leaf samples of sweet potatoes for unknown reasons (Dr. K. W. Yeh, personal communication).…”