Characterization of the Proteins from Vigna unguiculata Seeds

Abstract

The proteins from Vigna unguiculata (L.) Walp. (cowpea) seeds were investigated. Globulins constitute over 51% of the total seed protein, with albumins composing approximately 45%. The globulins may be fractionated by native electrophoresis or anion exchange chromatography into three main components, which were termed (in decreasing order of anodic mobility) alpha-vignin, beta-vignin, and gamma-vignin. alpha-Vignin, with a sedimentation coefficient of 16.5S, is a major, nonglycosylated globulin, composed of a major 80 kDa subunit, which upon reduction, produces two polypeptides (20 and 60 kDa). beta-Vignin, with a sedimentation coefficient of 13S, is a major, glycosylated globulin, composed of two main polypeptides (55 and 60 kDa) with no disulfide bonds. Finally, gamma-vignin, a minor globulin, is composed by one main type of subunit (22 kDa), which upon reduction, is converted into a single, apparently heavier polypeptide chain (30 kDa) due to the presence of an internal disulfide bond. Immunological analyses revealed structural homology between beta-vignin and beta-conglutin (the vicilin from Lupinus seeds) but not between alpha- or gamma-vignins and their Lupinus counterparts. Haemagglutination activity toward trypsinized rabbit erythrocytes was found exclusively in the albumin fraction and was strongly inhibited by N-acetylglucosamine or chitin.

Analysis of common bean expressed sequence tags identifies sulfur metabolic pathways active in seed and sulfur-rich proteins highly expressed in the absence of phaseolin and major lectins

“…In most legume crops, α-subunits of 11S globulins have an apparent molecular weight of approximately 40 kD. By contrast, P. vulgaris and V. unguiculata [58] share a single, dominant high molecular weight legumin whose α-subunit has an apparent molecular weight of approximately 60 kD. Similarly, in L. japonicus , two of three major legumins, the legumin storage proteins 2 and -3, which are closely related to the P. vulgaris legumin, have α-subunit apparent molecular weights of 55 and 60 kD, respectively [36].…”

Antioxidant activity ofVigna unguiculataL. walp and hard-to-cookPhaseolus vulgarisL. protein hydrolysates

“…Legumes are widely consumed in southeastern Mexico as a major dietary protein source in both human and animal diets. Cowpea (Vigna unguiculata L. walp) is a major legume crop worldwide, particularly in tropical and subtropical areas (Freitas, Teixeira, & Ferreira, 2004). Common bean (Phaseolus vulgaris L.) has been a dietary staple in Mexico for millennia, although inadequate postharvest handling and storage techniques (i.e.…”

Production and characterization of cowpea protein hydrolysate with optimum nitrogen solubility by enzymatic hydrolysis using pepsin

“…Two major bands of about 65 and 40 kDa and minor bands of about 70–96 kDa were observed on the electrophoretic profile of the concentrate. The two major bands probably correspond to the subunits of vignin (7S globulin), while the minor band of 96 kDa is characteristic of the albumin fraction of cowpea protein as reported by Freitas et al Enzymatic hydrolysis of cowpea protein concentrate was accompanied by the complete degradation of polypeptides of 70–96 kDa, and the partial degradation of polypeptides of 40 and 65 kDa, as observed by the complete or partial loss of intensity of the corresponding bands. It could be suggested that the partially degraded polypeptides were probably rich in hydrophobic amino acids.…”