Identification of Soluble Proteins and Interaction with Mannan in Mucilage of Dioscorea opposita Thunb. (Chinese Yam Tuber)

Abstract

In this study, we analyzed the influence of proteins and polysaccharides on the viscous properties of mucilage extracted from Dioscorea opposita Thunb. (Chinese yam). The viscosity of the mucilage was greatly reduced by treatment with protease or mannanase, although not by treatment with cellulase. These results show that the interactions with mannan of certain soluble proteins in the mucilage play an important role in its viscosity, so we identified the major soluble proteins present. Chinese yam mucilage contained at least nine types of major soluble proteins, some of which showed a high percentage of identity with dioscorin, mannan-binding lectin and other functional proteins in the N-terminal amino acid sequence. From these findings, it was suggested that the viscosity of Chinese yam mucilage may be caused by interaction between mannan and soluble proteins such as mannan-binding lectin.