Abstract
The mycelium of Coprinus phlyctodosporus accumulated mannitol during the vegetative growth period but more than half of the amount was decreased by translocation into the fruit-bodies during development. The mannitol content in the fruit-bodies increased during their development. The mycelium only contained NAD-MDH, but the fruit-bodies contained both NADP- and NAD-MDHs. NAD-MDH in mycelium continue to increase until the fruiting initiation, and then began to decrease thereafter. On the other hand, both NAD- and NADP-MDH activities in the fruit-bodies increased until the middle stage of development and then decreased with maturation. NAD-MDH reactions for the mannitol formation in both mycelium and fruit-bodies showed the optimum pH at 7.0, and its Km values for fructose and NADH were 6.0×10^<-2> M and 1.0×10^<-5>M, respectively. The mannitol oxidation by NAD-MDH showed the maximum activity at pH 8.8, and its Km values for mannitol and NAD were 2.8×10^<-3>M and 2.3×10^<-4>M, respectively. On the other hand, the Km values of NADP-MDH in fruit-bodies for fructose and NADPH at pH 7.0 were 3.3×10^<-1> and 1.4×10^<-5>M. Those for mannitol and NADP were 1.1×10^<-2>M and 1.0×10^<-4>M at the optimum pH of 9.6, respectively. These results suggest that mannitol was synthesized in the mycelium and translocated into the fruit-bodies, at which it was converted to fructose by NADP-MDH and then entered into the glycolytic pathway of this mushroom.
