Primary structures of proteinase inhibitors from Phaseolus vulgaris var. nanus (cv. Borlotto).

The primary structures of two trypsin-chymotrypsin inhibitors from Phaseolus vulgaris var. nanus (bush bean, cv. Borlotto), PVI-3(2) und PVI-4, were derived from automated Edman degradation data, amino acid composition and manual Edman degradation results of enzymatic fragments and homology with other Bowman-Birk type proteinase inhibitors. The highest degrees of homology were observed between PVI-3(2) or PVI-4 and the trypsin-chymotrypsin inhibitors from lima beans (LBI I, IV and IV', 86%), black-eyed peas (BTCI, 81%), and, in part, adzuki beans (ABI I, II and II', 74-77%). Similarly, the primary structure of the trypsin-elastase inhibitor from the same source, PVI-3(1), was deduced which showed highest homology with that of the trypsin-elastase inhibitor GBI II from garden beans (92%), followed by GBI II' from garden beans (86%) and C-II from soybeans (71%). In contrast, homology between PVI-3(2) and PVI-4 on the one hand and PVI-3(1) on the other was relatively low (61%).