The action of pepsin on the reserve proteins of some leguminous seeds

Abstract

The action of pepsin on the 11-S and 7-S proteins of vetch, 11-S protein of soybean and 7-S protein of Phaseolus vulgaris was investigated. The first three proteins are hydrolyzed almost completely, the rate of hydrolysis being close to that of hemoglobin, while the hydrolysis of Ph. vulgaris 7-S protein stops after the cleavage of only 2,4% of peptide bonds. The nonhydrolyzable high molecular weight core makes up to 87% of the initial protein and differs from the latter in its electrophoretic mobility and sedimentation coefficient. The action of pepsin does not increase the digestibility of Ph. vulgaris 7-S protein by trypsin. After the consecutive action of these enzymes about two thirds of the protein remain unhydrolyzed. The digestion of Ph. vulgaris 7-S protein by pepsin is completed only after its denaturation by heat treatment or by the action of 6 M guanidine hydrochloride.

Comparative digestibility of legume storage proteins

“…However, native phaseolin is extremely resistant to pepsin digestion. Pepsin pretreatment does not increase digestion of native phaseolin by trypsin (Vaintraub et al, 1979), nor can a combination of trypsin, chymotrypsin, and pepsin overcome its resistance to proteolysis (Liener and Thompson, 1980). The order in digestibility of the major storage proteins agrees with the comparative results of nutritive value for the unheated legume seeds.…”

“…The inaccessibility of phaseolin to enzymes has been attributed to its structural properties (Romero and Ryan, 1978), particularly its compact structure (Chang and Satterlee, 1981). Native phaseolin is much more resistant to pepsin than trypsin and is more rapidly hydrolyzed by trypsin than chymotrypsin (Romero and Ryan, 1978;Vaintraub et al, 1979; Liener and Thompson, 1980;Deshpande and Nielsen, 1987). Trypsin and chymotrypsin have been shown to cleave native phaseolin in such a way that the halves of the molecule remain intact (Liener and Thompson, 1980;Bradbear and Boulter, 1984;Deshpande and Nielsen, 1987).…”

“…One research group (Vaintraub et al, 1976(Vaintraub et al, ,1979 that native glycinin is more readily hydrolyzed by trypsin, chymotrypsin, or pepsin than is native phaseolin. However, results from studies that report the degradation of legume storage proteins by proteinases generally cannot be compared since digestion conditions differ.…”

Protein Quality Assessment of Computer Optimized Weaning Formulas

“…The exception was nonextruded Formula 3 which contained 35% cowpea flour. Extrusion cooking of this formula brought the PER in line with that of the others, implying that the low value for the unextruded formula was due to the presence of antinutritionals and perhaps to the resistance of raw cowpea protein to digestion by mammalian proteases (Romero and Ryan 1978;Vaintraub 1979). Unextruded Formula 2, which contains 35.1% cowpea flour, was not included in the feeding studies due to limited availability.…”

Penentuan Daya Cerna Protein In Vitro Ikan Bawal (Colossoma Macropomum) pada Umur Panen Berbeda

“…Faktor eksogenus yaitu interaksi protein dengan polifenol, fitat, karbohidrat, lemak, dan protease inhibitor (Duodu et al, 2003;Ikeda et al, 1986). Sedangkan faktor endogenus terkait dengan karakterisasi struktur protein seperti struktur tersier, kuartener, serta struktur yang dapat rusak oleh panas dan perlakuan reduksi (Deshpande & Damodaran, 1989;Ikeda et al, 1991;Vaintraub et al 1979).…”