IUBMB Enzyme Nomenclature

EC 2.4.2.2

Accepted name: pyrimidine-nucleoside phosphorylase

Reaction: (1) uridine + phosphate = uracil + α-D-ribose 1-phosphate
(2) thymidine + phosphate = thymine + 2-deoxy-α-D-ribose 1-phosphate
(3) 2'-deoxyuridine + phosphate = uracil + 2-deoxy-α-D-ribose 1-phosphate

Other name(s): Py-NPase; pdp (gene name)

Systematic name: pyrimidine-nucleoside:phosphate (2'-deoxy)-α-D-ribosyltransferase

Comments: Unlike EC 2.4.2.3, uridine phosphorylase, and EC 2.4.2.4, thymidine phosphorylase, this enzyme can accept both the ribonucleoside uridine and the 2'-deoxyribonucleosides 2'-deoxyuridine and thymidine [3]. The reaction is reversible, and the enzyme does not distinguish between α-D-ribose 1-phosphate and 2'-deoxy-α-D-ribose 1-phosphate in the synthetic direction.

Links to other databases: BRENDA, EXPASY, GTD, KEGG, PDB, CAS registry number: 9055-35-0

References:

1. Friedkin, M. and Kalckar, H. Nucleoside phosphorylases. In: Boyer, P.D., Lardy, H. and Myrbäck, K. (Eds), The Enzymes, 2nd edn, vol. 5, Academic Press, New York, 1961, pp. 237-255.

2. Saunders, P.P., Wilson, B.A. and Saunders, G.F. Purification and comparative properties of a pyrimidine nucleoside phosphorylase from Bacillus stearothermophilus. J. Biol. Chem. 244 (1969) 3691-3697. [PMID: 4978445]

3. Hamamoto, T., Noguchi, T. and Midorikawa, Y. Purification and characterization of purine nucleoside phosphorylase and pyrimidine nucleoside phosphorylase from Bacillus stearothermophilus TH 6-2. Biosci. Biotechnol. Biochem. 60 (1996) 1179-1180. [PMID: 8782414]

4. Okuyama, K., Hamamoto, T., Noguchi, T. and Midorikawa, Y. Molecular cloning and expression of the pyrimidine nucleoside phosphorylase gene from Bacillus stearothermophilus TH 6-2. Biosci. Biotechnol. Biochem. 60 (1996) 1655-1659. [PMID: 8987664]

5. Pugmire, M.J. and Ealick, S.E. The crystal structure of pyrimidine nucleoside phosphorylase in a closed conformation. Structure 6 (1998) 1467-1479. [PMID: 9817849]

[EC 2.4.2.2 created 1961, modified 2013]


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