A Proteolytic Inhibiting Substance in the Extract From Unheated Soy Bean Meal

Evidence, isolation, purification, and some properties of a trypsin inhibitor in Lathyrus sativus

“…The presence of a trypsin inhibitor in soybeans and navybeans has been reported (Bowman, 1944;Ham and Sandstedt, 1944). The existence of a trypsin inhibitor in Indian pulses and vegetables has also been reported by different workers Bhandarkar, 1954, 1955), in sweet potato (Sohonie and Honawar, 1956), and in field beans (Banerjee and Sohonie, 1969).…”

Nutritive value of legume seed proteins

“…Osborne and Mendel (1917) observed that while raw soybeans failed to support growth of animals, previous cooking of the soybeans increased their growth-promoting properties to what would be expected from the previously determined amino acid composition of the soybean glycinin (Osborne and Clapp, 1907). Trypsin inhibitor (Ham and Sandstedt, 1944) and hemagglutinin (Liener and Pallansch, 1952) are believed to be the heatlabile growth inhibitors of raw soybeans. There is an optimal amount of heating of soybeans that gives maximum nutritive value, and when soybeans are heated more than this there is a loss of nutritive value of the proteins (Evans and McGinnis, 1946) and a decreased content (Clandinin et al, 1947) and availability (Mc-Ginnis and Evans, 1947) of lysine.…”

Phytohemagglutinins. Their nutritional significance

“…The beneficial effect of heat on the nutritional value of soybean protein was first observed by Osborne and Mendel (1917) and, with the demonstration of a heat-labile trypsin inhibitor in raw soybeans (Ham and Sandstedt, 1944), it was generally assumed that this was the factor responsible for the poor nutritive quality of the unheated bean. Liener et al (1949), however, presented evidence to show that the trypsin inhibitor could not account for all of.…”

“…Since these same legumes are the very plants in which the phytohemagglutinins can be found (Table I), it is indeed curious that one finds so little information in the literature regarding what would seem like an obvious relationship between the phytohemagglutinins and the poor nutritive value of raw legumes. Perhaps one explanation for this vacuum lies in the fact that the discovery of a trypsin inhibitor in soybeans (Ham and Sandstedt, 1944;Kunitz, 1945) and other legumes (Borchers et al, 1947) served to divert attention from the phytohemagglutinins, and nutritionists seem to have become preoccupied with studying the role of the trypsin inhibitors, particularly in the soybean. It is my intent, therefore, to try to redirect your attention to the role that the phytohemagglutinins might play in affecting the nutritional properties of plant protein.…”