Activities of some Enzymes Involved in Metabolism of Carbohydrate during Sporophore Development in Coprinus cinereus

Measurements of the specific activities of representative enzymes of the pentose phosphate cycle, Embden-Meyerhof-Parnas (EMP) pathway and the tricarboxylic acid (TCA) cycle in Coprinus cinereus sporophores at different stages of development indicate that glycolysis is the major route of carbohydrate catabolism throughout sporophore development. Enzymes of the pentose phosphate cycle were always at lower specific activities than the enzymes of the EMP pathway, and the activities of the pentose phosphate cycle enzymes declined drastically as development proceeded. This conflicts with the findings for Agaricus bisporus, but the changes in some enzymes were qualitatively similar to those occurring in the development of sporophores of Schizophyhm commune. A number of enzymes of the TCA cycle were detected, but there was no 2-oxoglutarate dehydrogenase activity nor increase of isocitrate lyase activity over the basal repressed leve!. However, glutamate decarboxylase and 4-aminobutyrate aminotransferase were detected, suggesting that the inoperative a-oxoglutarate dehydrogenase is by-passed through the glutamate decarboxylation loop. The results are discussed in relation to the changes which also occur in the specific activities of the two glutamate dehydrogenase enzymes during development of the sporophore.