Abstract
Seeds of kidney beans, Phaseolus vulgaris, contain α-amylase inhibitor, phaseolamin, which inhibits specifically α-amylase activity from mammalian sources, A sensitive and specific staining method for identifying the α-amylase inhibitor activity in the disc electrophoresis gel was developed, using the iodine-starch complex. With this technique, 10ng of amylase inhibitor was demonstrated as a sharp band.
Among the leguminous seeds only kidney beans contained α-amylase inhibitors. They have different mobilities in compliance with classes of kidney beans. They were separated in 4 forms, Ai-I, Ai-II, Ai-III, and Ai-IV, numbered with the lower ones given to the forms with the higher mobility. Shirobanamame contained Ai-I and Ai-II, Daifuku and Kintoki Ai-III, and all other kinds of kidney beans Ai-IV.
Inhibitory activity of the inhibitor was weakened by removal of calcium ion from α-amylase.
