RESISTANCE OF CRANBERRY BEAN (PHASEOLUS-VULGARIS) ALPHA-AMYLASE INHIBITOR TO INTRALUMINAL DIGESTION AND ITS MOVEMENT ALONG RAT GASTROINTESTINE - FURTHER INVESTIGATION USING A RADIOACTIVE PROBE AND SPECIFIC ANTISERUM

Cranberry bean (Phaseolus vulgaris) alpha-amylase inhibitor (CBAI) was treated with [C-14]HCHO and NaBH-4 to modify the lysyl epsilon-amino group. [C-14] Labelled inhibitor thus obtained was used as a radioactive probe. The reductive methylation of CBAI caused neither a significant change in its susceptibility to digestive enzymes nor in its immuno-reactivity with rabbit antiserum. Consequently, gastric emptying and intestinal transit of the inhibitor was represented by radioactivity measurement and simultaneously complemented by quantification due to single radial immuno diffusion. As a result, the bulk of the inhibitor was found not to undergo digestion and absorption but to pass through the small intestine without much loss of antigenicity and radioactivity.