Relative importance of phytohemagglutinin (lectin) and trypsin-chymotrypsin inhibitor on bean (Phaseolus vulgaris L) protein absorption and utilization by the rat

• Published in: Journal of Nutritional Science and Vitaminology 1998, Vol.44(5), pp.685-696
• Main Authors: Carvalho, M.R.B. (Instituto de Tecnologia de Alimentos (Brasil)), Sgarbieri, V.C
• Format: Article
• Language: English
• Subjects: Absorption; Animals; antinutritional factor; Biological and medical sciences; Caseins - metabolism; CHYMOTRYPSIN; CHYMOTRYPSINE; Dietary Proteins - metabolism; Digestion; dry bean; ENZYME INHIBITORS; Fabaceae - chemistry; Fabaceae - metabolism; Feeding. Feeding behavior; Freeze Drying; Fundamental and applied biological sciences. Psychology; Hot Temperature; INHIBIDORES DE ENZIMAS; INHIBITEUR D'ENZYME; LECTINAS; LECTINE; LECTINS; Male; Nitrogen - metabolism; Nutritive Value; PHASEOLUS VULGARIS; phytohemaggluti-nin (lectin); Phytohemagglutinins - analysis; Phytohemagglutinins - pharmacology; Phytohemagglutinins - toxicity; Plant Lectins; Plants, Medicinal; PROTEINAS; PROTEINE; PROTEINS; QUIMOTRIPSINA; RAT; RATA; RATS; Rats, Wistar; toxicity; TRIPSINA; TRYPSIN; trypsin inhibitor; Trypsin Inhibitor, Bowman-Birk Soybean - pharmacology; TRYPSINE; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Weight Gain - drug effects
• ISSN: 0301-4800; 1881-7742
• DOI: 10.3177/jnsv.44.685

The main objective of this work was to perform a comparative study of the antinutritional and/or toxic properties of phytohemagglutinin and trypsin-chymotrypsin inhibitor extracted from the seed of a commercial cultivar of edible bean used in Brazil. Bean proteins were extracted in acidic salt solution and fractionated by dialysis and centrifugation, then freeze-dried. The total freeze-dried bean extract and the globulin or albumin protein fraction were resuspended in distilled water and heated (100 degrees C, 30 min) for inactivation of hemagglutinin. Diets were prepared with unheated bean protein fractions and heated ones (100% trypsin inhibitor activity, but 0% phytohemagglutinin activity). As a result, the inhibition of growth and poor dietary protein utilization were observed in rats fed diets containing unheated bean protein fractions, but not in rats fed diets containing heated fractions. It was thus assumed that phytohemagglutinin is the main antinutritional and toxic factor in dry bean (Phaseolus) protein and that trypsin inhibitor (Bowman-Birk type) did not interfere with rat growth