YLR209c Encodes Saccharomyces cerevisiae Purine Nucleoside Phosphorylase

Abstract
The yeast YLR209c ( PNP1 ) gene encodes a protein highly similar to purine nucleoside phosphorylases. This protein specifically metabolized inosine and guanosine. Disruption of PNP1 led to inosine and guanosine excretion in the medium, thus showing that PNP1 plays an important role in the metabolism of these purine nucleosides in vivo.