Electrophoretic analysis of glycoprotein from yam (Dioscorea oppsita Thunb.) mucilage

摘要

The mucilage in yam tubers is a very important factor for the viscosity of yam, but there are a number of unclarified points regarding protein in yam mucilage. Therefore, the present report aims at characteristics of protein of mucilage from three kinds of yams (Tsukuneimo, Ichoimo, Nagaimo). The results obtained were as follows: The yam mucilage were composed mainly of sugar (20-40 percnet) and protein (60-80 percent). Viscosity, sugar and protein contents of mucilage from yam indicated a high rate in the following order. Tsukuneimo, Ichoimo, and Nagaimo. The viscous protein in mucilage gave several protein (490, 280, 160 and 76kDa) or glycoprotein bands (56, 32, 28 and 20kDa) on Native and SDS-PAGE. Isoelectric points of the protein in mucilage were mainly pH4.7-5.0 on isoelectric focusing. However, the electrophoretic profiles of the protein in mucilage from the Nagaimo tuber differed from those of the Tsukuneimo and Ichoimo tubers.