Sugar, Sugar Phosphate and NADP(H) Levels in Agaricus bisporus Fruit Bodies

Abstract

Levels of glucose 6-phosphate, fructose 6-phosphate, 6-phosphogluconate, fructose 1,6-bisphosphate, trehalose, glucose, fructose, mannitol, NADP and NADPH were determined in Agaricus bisporus fruit body tissues. Of the phosphorylated sugars, glucose 6-phosphate was present in the largest quantity, at approximately 1·5 μmol (g fresh wt)–1. Fructose was detected in larger quantities than in previous investigations. NADP and NADPH levels were found to be in the range 45–200 nmol (g fresh wt)–1. with NADP/NADPH ratios between 0·58 and 1·66. The anabolic reduction charge showed a negative relationship with mannitol level. Mass action ratios calculated for glucose-6-phosphate dehydrogenase were several orders of magnitude below the reported k eq for the reaction. The mass action ratio for glucose-6-phosphate dehydrogenase showed a significant correlation with trehalose content over the period of sampling. The results are discussed with reference to possible controls of the pentose phosphate pathway and mannitol synthesis.