An antioxidant glycoprotein (Fraction AIV-2) with molecular weight of 27.2 kDa was purified from the ethanol-soluble protein hydrolysate of Mustelus griseus muscle. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of Fraction AIV-2 reached up to 96.73±2.33% and was higher than that of ascorbic acid at the concentration of 5.0mg/mL. Total protein and carbohydrate contents of Fraction AIV-2 were 62.65±0.63% and 33.49±1.60%, respectively. Seventeen amino acids were identified in Fraction AIV-2, most of which are serine. GC-MS analysis showed that Fraction AIV-2 was composed of fucose, arabinose, galactose, glucose and mannose with the ratio of 1.00:1.53:7.27:9.07:2.09. The FT-IR spectrum of Fraction AIV-2 showed typical characteristics of polysaccharide and protein. For Fraction AIV-2, the changes of ultraviolet absorption curve, amino acid composition after the β-elimination reaction and its deglycosylation with the treatment of N-glycosidase F suggested that both O-glycosidic and N-glycosidic bonds were involved in the polysaccharide and protein moieties.
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