Considerable amounts of GTP, GMP, adenosine, guanine, and adenine nccnmulated in Neurospom crasaa when a cult'ure grown on low phosphate (0.01%) medium was transferred to a high phosphate (19;) medium. The levels of alkaline phosphatase, nucleotidase, and nucleosidase decreased by 2.4, 5.4, and 3 folds, respectively, in cultures grown on high phosphate medium. Substrate kinetics of these enzymes revealed that: (1) alkaline phosphatase isolated from the organism grown on low phosphate medium demonstrates nonlinear reciprocal plots with two distinct apparent K w values for ,4-glycerophonphate compared to one apparent, K m value (associated with 32% decrease in the apparent VIllar value)