Reactome | HPRT1 tetramer transfers phosphoribosyl group to 6MP to form 6TIMP

HPRT1 tetramer transfers phosphoribosyl group to 6MP to form 6TIMP

Stable Identifier

R-HSA-9748951

Type

Reaction [transition]

Species

Homo sapiens

Compartment

cytosol

Synonyms

6MP--HPRT1-->6TIMP

ReviewStatus

5/5

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HPRT1 tetramer transfers phosphoribosyl group to 6MP to form 6TIMP

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6-mercaptopurine (6MP) can be metabolized via three competing pathways; oxidation by xanthine oxidase (XDH), methylation by thiopurine methyl S-transferase (TPMT) and conversion by hypoxanthine-guanine phosphoribosyltransferase (HPRT1).

Hypoxanthine-guanine phosphoribosyltransferase tetramer (HPRT1) catalyzes the transfer of phosphoribosyl from 5-phosphoribosyl 1-pyrophosphate (PRPP) to 6-mercaptopurine (6MP), to form 6-thioinosine 5’-monophosphate (6TIMP) (Krenitsky et al. 1969, Xu et al. 1997). This is the metabolic branch for the formation of the pharmacologically active 6-thioguanine nucleotides (6-TGNs).

Literature References

PubMed ID	Title	Journal	Year
5767308	Human hypoxanthine phosphoribosyltransferase. I. Purification, properties, and specificity Elion, GB, Krenitsky, TA, Papaioannou, R	J Biol Chem	1969
9132023	Kinetic mechanism of human hypoxanthine-guanine phosphoribosyltransferase: rapid phosphoribosyl transfer chemistry Xu, Y, Eads, J, Sacchettini, JC, Grubmeyer, C	Biochemistry	1997