Klebsiella sp. LF 1202, previously isolated from soil assimilates adenosine as a sole source of carbon and nitrogen. The bacterium inducibly formed both purine nucleoside phosphorylase (PNPase) and uridine phosphorylase (UPase), simultaneously, when cultured in adenosine-containing medium or uridine-containing medium. PNPase and UPase were purified to homogeneity on SDS-PAGE, and some properties were examined. Enzymic production of 1-beta-D-ribofuranosyl-1, 2, 4,-triazole-3-carboxamide (Virazole), an anti-DNA virus pharmaceutical drug, was demonstrated using the combined reaction of both enzymes.