SOME CHARACTERISTICS OF DIGESTIVE ALPHA-GLYCOSIDASES FROM ADULTS OF BRUCHUS-AFFINIS FROLICH, IN RELATION WITH INTESTINAL PH

Intestinal pH, determined in situ from the colours of indicator dyes i ngested with sucrose, ranged between 6.5-5.5 in the foregut and midgut , and 5.5-4.5 in the hindgut. An identical optimal pH value of 5.5 was determined for sucrase, maltase and amylase. Under physiological cond itions of pH (6.0), the kinetics of alpha-glycosidase activity showed that maltase was by far the most active, followed by sucrase and then amylase. Substrate specificities and preliminary characterization of t he major digestive alpha-glycosidases of B. affinis suggest a well-fit ted adaptation to the seasonal variations of diet composition.