Bradykinin Inactivating Enzymes from Red Kidney Beans (Phaseolus vulgaris) and Potatoes (Solanum tuberosum)

Abstract

Strong kininase activity was found in various kinds of bean seed. The extract from 1g of varieties of beans inactivated 50_??_410 nmoles bradykinin when incubated for 1min at pH 7.4 and 30°C. A protease with kininase activity was partially purified from red kidney beans (Phaseolus vulgaris). The molecular weight of the bean protease was 73, 000, and its isoelectric point was 4.6. The enzyme appeared to be a metalloenzyme with a specificity similar to that of leucine aminopeptidase. The properties of the bean enzyme are similar to those of a bradykinin inactivating enzyme from potatoes (Solanum tuberosum).