PURIFICATION AND PROPERTIES OF SOYBEAN PROTEIN INHIBITORS OF PROTEOLYTIC ENZYMES

A number of structurally dissimilar globular proteins that can inhibit the activity of certain proteinases, such as trypsin and α-chymotrypsin, constitute part of the seed protein in the soybean plant. These “soybean trypsin inhibitors,” which can be inactivated by moist heat, contribute to the antinutritional quality of raw meal. Two distinct factois, the Kunitz and the Bowman-Birk inhibitors, have been subjected to physical, chemical, biochemical, and nutritional study. The Kunitz and most other protein inhibitors isolated from plant or animal sources are very efficient in abolishing or reducing tryptic activity; some, like the Bowman-Birk inhibitor, are almost equally active against tryptic and α-chymotryptic activity. Much attention has been focused on the interaction between trypsin and the Kunitz inhibitor with the expectation of formulating a general mechanism of action for these and other natural inhibitors. © 1969, American Chemical Society. All rights reserved.