CBlock Clinical Studies

January 1, 1998 (c)

Characterization of kintoki bean (Phaseolus vulgaris) alpha-amylase inhibitor: inhibitory activities against human salivary and porcine pancreatic alpha-amylases and activity changes by proteolytic digestion.

Yoshikawa, H.; Kotaru, M.; Tanaka, C.; Ikeuchi, T.; Kawabata, M.

Journal of J Nutr Sci Vitaminol (Tokyo), vol. 45
January 1, 1998

The effects of some experimental parameters on alpha-amylase inhibition by an alpha-amylase inhibitor from kintoki bean were examined. The rate of inhibition against pancreatic alpha-amylase increased with a rise in temperature to 50 degrees C, but the inhibition of salivary alpha-amylase reached a maximum above 35 degrees C. Although an increase in NaCl concentration to 1.5 M caused an increase in the inhibitory activities against both amylases, these inhibitory activities tended to decrease above 1.5 M NaCl. The effects of proteolytic digestion on the amylase inhibitory activity were also studied. The inhibitor was slightly inactivated by pepsin digestion for 2 h. Although the inhibitor rapidly lost the inhibitory activity by chymotrypsin digestion within 2 h, it was quite resistant to proeolytic digestion by trypsin.