Biochemical Studies of Bacterial Sporulation and Germination V. PURINE NUCLEOSIDE PHOSPHORYLASE OF VEGETATIVE CELLS AND SPORES OF BACILJ,Ufi

1. Urine nucleoside phosphorylase was purified from the vegetative cells and spores of Bacillus cereus var. terminalis. The enzymes from the vegetative cell and the spore were found to have similar physical and catalytic properties. A mutant (strain 29) with only 2% of the level of enzyme activity in the vegetative cell also had a comparably low level in the spore. 2. The vegetative cell enzyme is inducible by inosine. Nevertheless, sporulation in the absence of inducer leads to high enzyme levels in the sporulating cell and spore, presumably due to endogenous changes during the stationary phase preceding spore development. The enzyme activity in mutant strain 29 appeared to be constitutive. 3. Spores of mutant strain 29 with only 3% of the level of enzyme activity of wild type spores germinated in response to inosine as rapidly and as completely as did the wild type spores.