Guanosine-5'-triphosphate,3'-diphosphate diphosphatase

In enzymology, a guanosine-5'-triphosphate,3'-diphosphate diphosphatase (EC 3.6.1.40) is an enzyme that catalyzes the chemical reaction

guanosine 5'-triphosphate,3'-diphosphate + H₂O ${\displaystyle \rightleftharpoons }$ guanosine 5'-diphosphate,3'-diphosphate + phosphate

Thus, the two substrates of this enzyme are and H₂O, whereas its two products are and phosphate.

This enzyme belongs to the family of hydrolases, specifically those acting on acid anhydrides in phosphorus-containing anhydrides. The systematic name of this enzyme class is guanosine-5'-triphosphate,3'-diphosphate 5'-phosphohydrolase. Other names in common use include pppGpp 5'-phosphohydrolase, guanosine-5'-triphosphate,3'-diphosphate pyrophosphatase, guanosine 5'-triphosphate-3'-diphosphate 5'-phosphohydrolase, guanosine pentaphosphatase, guanosine pentaphosphate phosphatase, guanosine 5'-triphosphate 3'-diphosphate 5'-phosphatase, and guanosine pentaphosphate phosphohydrolase. This enzyme participates in purine metabolism.

Structural studies[]

As of late 2007^{[needs update?]}, two structures have been solved for this class of enzymes, with PDB accession codes 1T6C and 1T6D.

References[]

• Hara A, Sy J (1983). "Guanosine 5'-triphosphate, 3'-diphosphate 5'-phosphohydrolase Purification and substrate specificity". J. Biol. Chem. 258 (3): 1678–83. PMID 6130093.