Raw soy and purified proteinase inhibitors induce the appearance of inhibitor-resistant trypsin and chymotrypsin activities in Wistar rat duodenal juice.
Rats were fed raw soybeans or purified soybean proteinase inhibitors by tube to see whether they were able to produce inhibitor-resistant trypsin, as previously demonstrated in humans. Their duodenal chyme contained only 20-50% of the enzymatic activities of animals fed bovine serum albumin (BSA) as test protein. However, both tryptic and chymotryptic activities had considerable resistance to low- and high-molecular-weight inhibitors of serine proteinases. In particular, the tryptic activity demonstrated a high degree of inhibitor resistance. Human alpha 1-antitrypsin and lima bean inhibitor in amounts that inhibited bovine serum albumin-induced trypsin completely caused only 2-12% inhibition of the raw soybean-induced tryptic activity. The inhibitor-resistant tryptic and chymotryptic activities after raw soybean instillation might be caused by the Bowman-Birk and Kunitz trypsin inhibitors. The physiologic significance of an inhibitor-resistant trypsin might be to assure activation of other pancreatic proenzymes. The results of the present rat experiments confirm the previous findings of inhibitor-resistant trypsin in humans.
Holm
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Institute for Nutrition Research, University of Oslo, Norway.
Jørgensen
A
A
Hanssen
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LE
D000818:Animals; D002918:Chymotrypsin / Q000096:biosynthesis / Q000187:drug effects*; D004386:Duodenum / Q000201:enzymology; D007419:Intestinal Secretions / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D011480:Protease Inhibitors / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013025:Glycine max; D014357:Trypsin / Q000096:biosynthesis / Q000187:drug effects*; D014358:Trypsin Inhibitor, Bowman-Birk Soybean / Q000494:pharmacology; D014360:Trypsin Inhibitor, Kunitz Soybean / Q000494:pharmacology; D000515:alpha 1-Antitrypsin / Q000494:pharmacology
D011480:Protease Inhibitors; D014358:Trypsin Inhibitor, Bowman-Birk Soybean; D000515:alpha 1-Antitrypsin; D014360:Trypsin Inhibitor, Kunitz Soybean; D002918:Chymotrypsin; D014357:Trypsin