Journal of Microbiology

Purification and characterization of purine nucleoside phosphorylase (PNP) in micrococcus luteus: Choi , Hye Seon; J. Microbiol. 1996;34(1):82-89.

Abstract: Purine nucleoside phosphorylase (PNP) was purified in Micrococcus luteus (M. luteus) using streptomycin sulfate and amomonium sulfate fractionation, three times by a Sephadex G-100 gel filtration and a DEAE-Sephadex A-50 ion exchange chromatography. The enzyme was purified 72 folds with a 11% recovery and showed a single band in a nondenaturing gel electrophoresis. The M. W. of PNP turned out to be 1.35 × 10^5 dalton in G-150 gel filtration chromatography. The stability of the enzyme was increased by treatment with both substrates, MgCI₂or CaCI₂, but not significantly kcal/mol. M. luteus PNP catalyzed the phosphorolysis of inosine, deoxyinosine, guanosine and deoxyguanosine with the Km value of 1.5 × 10^-3 M, 3.0 × 10^-3 M, 5.0 × 10^-4 M, respectively. The enzyme was reacted with adenosine, 1-methylnosine and 1-methylguanosine as substrates, which were shown to be poor substrates for mammalian enzyme.

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