Purine-nucleoside phosphorylase

In enzymology, a purine-nucleoside phosphorylase (EC number|2.4.2.1) is an enzyme that catalyzes the chemical reaction

:purine nucleoside + phosphate $ightleftharpoons$ purine + alpha-D-ribose 1-phosphate

Thus, the two substrates of this enzyme are purine nucleoside and phosphate, whereas its two products are purine and alpha-D-ribose 1-phosphate.

This enzyme belongs to the family of glycosyltransferases, specifically the pentosyltransferases. The systematic name of this enzyme class is purine-nucleoside:phosphate ribosyltransferase. Other names in common use include inosine phosphorylase, PNPase, PUNPI, PUNPII, inosine-guanosine phosphorylase, nucleotide phosphatase, purine deoxynucleoside phosphorylase, purine deoxyribonucleoside phosphorylase, purine nucleoside phosphorylase, and purine ribonucleoside phosphorylase. This enzyme participates in 3 metabolic pathways: purine metabolism, pyrimidine metabolism, and nicotinate and nicotinamide metabolism.

tructural studies

As of late 2007, 85 structures have been solved for this class of enzymes, with PDB accession codes PDB link|1A69, PDB link|1A9O, PDB link|1A9P, PDB link|1A9Q, PDB link|1A9R, PDB link|1A9S, PDB link|1A9T, PDB link|1B8N, PDB link|1B8O, PDB link|1ECP, PDB link|1FXU, PDB link|1G2O, PDB link|1I80, PDB link|1K9S, PDB link|1LV8, PDB link|1LVU, PDB link|1M73, PDB link|1N3I, PDB link|1NW4, PDB link|1OTX, PDB link|1OTY, PDB link|1OU4, PDB link|1OUM, PDB link|1OV6, PDB link|1OVG, PDB link|1PBN, PDB link|1PF7, PDB link|1PK7, PDB link|1PK9, PDB link|1PKE, PDB link|1PR0, PDB link|1PR1, PDB link|1PR2, PDB link|1PR4, PDB link|1PR5, PDB link|1PR6, PDB link|1PW7, PDB link|1PWY, PDB link|1Q1G, PDB link|1QE5, PDB link|1RCT, PDB link|1RFG, PDB link|1RR6, PDB link|1RSZ, PDB link|1RT9, PDB link|1TCU, PDB link|1TCV, PDB link|1TD1, PDB link|1ULA, PDB link|1ULB, PDB link|1V2H, PDB link|1V3Q, PDB link|1V41, PDB link|1V45, PDB link|1V48, PDB link|1VFN, PDB link|1VHJ, PDB link|1VHW, PDB link|1VMK, PDB link|1XE3, PDB link|1YQQ, PDB link|1YRY, PDB link|1Z33, PDB link|1Z34, PDB link|1Z35, PDB link|1Z36, PDB link|1Z37, PDB link|1Z38, PDB link|1Z39, PDB link|2A0W, PDB link|2A0X, PDB link|2A0Y, PDB link|2AC7, PDB link|2AI1, PDB link|2AI2, PDB link|2AI3, PDB link|2B94, PDB link|2BSX, PDB link|2I4T, PDB link|2ISC, PDB link|2OC4, PDB link|2OC9, PDB link|2ON6, PDB link|3PNP, and PDB link|4PNP.

References

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* Boyer, P.D., Lardy, H. and Myrback, K. (Eds.), The Enzymes, 2nd ed., vol. 5, Academic Press, New York, 1961, p. 237-255.
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External links

::"The CAS registry number for this enzyme class is CAS registry|9030-21-1."

Gene Ontology (GO) codes