Effect of low-dose irradiation on soybean protein solubility, trypsin inhibitor activity, and protein patterns separated by polyacrylamide gel electrophoresis

Abstract

to electrophoresis in 15% PAA for 16 h at 100 V and then stained with Coomassie Brilliant Blue R 250 (0.1% in 10% acetic acid and 20% methanol). Gels were destained in 10% acetic acid and 20% methanol.Poro-PAGE (5-25% PAA in Tris-borate buffer, pH 8.9) was carried out according to the method of Margolis and Kenrick (1968). Staining and destaining were carried out as described for SDS-PAGE.Electrophoresis was carried out on POOMA-PHOR apparatus (Labor Muller-3510 Hann-Mvinden).

Effect of Gamma Radiation on Protein Profile, Protein Fraction and Solubility’s of Three Oil Seeds: Soybean, Peanut and Sesame

“…The results are in agreement with the finding of Afify et al (1992a), Gralik and Warchalewski (2006) who showed that, irradiation of an aqueous solution of serum albumin or wheat albumin produced destruction in its amino acid content. The present results were in agreement with (Afify and Shousha, 1988) who reported that irradiation caused slight differences in albumin protein band intensities and inactivation of enzyme and polymerization and aggregation of simple protein. In globulin fraction, the intensities of the three major subunits with molecular weight 35, 30 and 20 K Da was increased as a result of gamma radiation doses and reached to maximum intensity with 7.5 KGy.…”

“…2). The results showed that most of major and minor bands of arachin and conarachin are denatured by gamma radiation rather than destructive because these fractions were re-solubilized in the SDS-ME fraction, esPeanut Albumin Peanut Globulin Peanut (Albumin + Globulin) Peanut (SDS, ME 2%) The changes in globulin fraction were probably due to radiation induced protein denaturation and degradation of the insoluble protein fraction as stated by Chow and Subha (1985), Afify and Shousha (1988), Afify et al (1992b). The slight changes in protein patterns after SDS-PAGE separation in sesame seeds after irradiation may be due to slight changes in bonds stabilized protein conformation or due to slight destructive in some aromatic and heterocyclic amino acid residues (Taub et al, 1976), and the possibility of rearrangement (Sonntage, 1987).…”

“…While it is known that gamma radiation is generally attributed to direct breakdown in protein or enhance the activity of lysozomal (proteolytic) enzyme, which help to aggregate the protein and decrease its solubility (Van Huystee and Verma, 1969). Therefore the irradiation dose used considered very important, since this dose could unfold protein to increase its solubility through the deamination of the protein (Rahma and Mostafa, 1988;Taha and Mohamed, 2004) or aggregate protein during disintegration through the decrease of the sulphahydryl group and increase the disulphide bond (Dogbevi et al, 1999b) and rearrangement of the small molecular weight protein to a high molecular weight and causes decrease in protein solubility (Afify and Shousha, 1988). …”

“…The rest of the proteins consist of whey proteins, such as γ-conglycinin (trimer of 170 KDa) (Hirano et al, 1987), the basic 7S globulin, lipoxygenase, agglutinins, and β-amylase, which belong to the 7S fraction (Iwabuchi and Yamaucho, 1987b). It is known that the physiochemical properties of proteins are modified by irradiation as reported by Hafez et al (1985), Afify and Shousha (1988) demonstrated that γ-irradiation caused molecular changes resulting in condensation or polymerization, degradation, hydrogen-bonding distribution and cleavages of intermolecular disulphide bonds (Casarett, 1968). Therefore, it is assumed that such molecular rearrangements bring about changes in secondary structure and distribution of the native conformation of soybean proteins, especially at higher dose levels.…”

“…Therefore, it is assumed that such molecular rearrangements bring about changes in secondary structure and distribution of the native conformation of soybean proteins, especially at higher dose levels. Afify and Shousha (1988) reported that SDS-PAGE proved that changes in protein subunit patterns could be identified in the 'Clark' cultivar depending to dose of γ-exposures. Three high molecular weight protein bands were detected in irradiated soybean cultivars by using Poro-PAGE 5-25% polyacrylamide.…”