Abstract:

In order to study the enzymatic mechanisms responsible for polysaccharides synthesis, the changes of polysaccharides, reducing sugar and metabolism-related enzymes in developing G. lucidum were analyzed. The contents of polysaccharides and reducing sugar were determined with phenol-sulfuric acid method and DNS method, respectively. The activities of six kinds of sugar metabolism-related enzymes were assayed. The correlation between polysaccharides accumulation and sugar metabolism-related enzymes was analyzed with SPSS 17.0. The change tendency of G. lucidum polysaccharides and reducing sugar changed similarly. The maximum content of polysaccharides and reducing sugar appeared in pileus phase. The polysaccharides accumulation was consistent with the change tendency of activities of six kinds of metabolism-related enzymes from the budding phase to the pileus phase, but not with that of G-6-PDH and MDH after the pileus phase. The content of polysaccharides had significant positive correlations with the activities of UDP-glucose pyrophosphorylase (UDPGPPlase), α-phosphoglucomutase (α-PGM) and phosphoglucose (PGI). However, there were not significant correlations between polysaccharides and the activities of hexokinase (HK), malate dehydrogenase (MDH) and glucose-6-phosphate dehydrogenase (G-6-PDH). UDPGPPlase, α-PGM and PGI play the important role in the biosynthesis of G. lucidum fruiting body polysaccharides.