GTP diphosphokinase

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In enzymology, a GTP diphosphokinase (EC 2.7.6.5) is an enzyme that catalyzes the chemical reaction

ATP + GTP $\rightleftharpoons$ AMP + guanosine 3'-diphosphate 5'-triphosphate

Thus, the two substrates of this enzyme are ATP and GTP, whereas its two products are AMP and guanosine 3'-diphosphate 5'-triphosphate.

This enzyme belongs to the family of transferases, specifically those transferring two phosphorus-containing groups (diphosphotransferases). The systematic name of this enzyme class is ATP:GTP 3'-diphosphotransferase. Other names in common use include stringent factor, guanosine 3',5'-polyphosphate synthase, GTP pyrophosphokinase, ATP-GTP 3'-diphosphotransferase, guanosine 5',3'-polyphosphate synthetase, (p)ppGpp synthetase I, (p)ppGpp synthetase II, guanosine pentaphosphate synthetase, GPSI, and GPSII. This enzyme participates in purine metabolism.

1 Structural studies
2 References
3 External links
- 3.1 Gene Ontology (GO) codes

[edit] Structural studies

As of late 2007, 4 structures have been solved for this class of enzymes, with PDB accession codes 1E3H, 1E3P, 1VJ7, and 2BE3.

[edit] References

IUBMB entry for 2.7.6.5
BRENDA references for 2.7.6.5 (Recommended.)
PubMed references for 2.7.6.5
PubMed Central references for 2.7.6.5
Google Scholar references for 2.7.6.5
Fehr S, Richter D (1981). "Stringent response of Bacillus stearothermophilus: evidence for the existence of two distinct guanosine 3',5'-polyphosphate synthetases". J. Bacteriol. 145: 68–73. PMID 6161916.
Sy J, Akers H (1976). "Purification and properties of guanosine 5', 3'-polyphosphate synthetase from Bacillus brevis". Biochemistry. 15: 4399–403. doi:10.1021/bi00665a008. PMID 184817.