EC number 2.7.6.5 ExPASy NiceZyme view | CAS number 63690-89-1 | |
In enzymology, a GTP diphosphokinase (EC 2.7.6.5) is an enzyme that catalyzes the chemical reaction
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.
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.