Purification and characterization of a new 11S globulin-like protein from grape (Vitis vinifera L.) seeds

Around 10 million tons of grape pomace containing 38-52% (on a dry matter basis) seeds was produced each year in the world, so how utilize these residual matters has been receiving great attention. In this study, 11S globulin-like protein (GSG) was isolated and purified from grape (Vitis vinifera L.) seeds by two consecutive cation exchange and size exclusion chromatography. A yield of 10 mg the protein from 1 kg seeds was obtained. The apparent molecular mass of the native GSG was found to be about 300 kDa. The protein consisted of two subunits with molecular masses of 25.5 and 40.0 kDa, respectively. MADLI-TOF-MS result showed that they were distinct from each other. N-terminal amino acid sequence of the 40.0 kDa subunit is RQQTSRQQKE. Amino acid composition analyses indicated that GSG contained all eight essential amino acids, while lysine was the first limiting amino acids. To the best of our knowledge, this is the first report on the purification of 11S globulin-like protein from Vitis vinifera L. seeds.