|PROSITE documentation PDOC00157|
Glucose-6-phosphate isomerase (GPI) (EC 18.104.22.168) or phosphoglucose isomerase (PGI) [1,2] is a dimeric enzyme that catalyzes the reversible isomerization of glucose-6-phosphate and fructose-6-phosphate. PGI is involved in different pathways: in most higher organisms it is involved in glycolysis; in mammals it is involved in gluconeogenesis; in plants in carbohydrate biosynthesis; in some bacteria it provides a gateway for fructose into the Entner-Doudouroff pathway. Besides it's role as a glycolytic enzyme, mammalian PGI can function as a tumor-secreted cytokine and an angiogenic factor (AMF) that stimulates endothelial cell motility. Mammalian PGI is also neuroleukin , a neurotrophic factor which supports the survival of various types of neurons.
The sequence of PGI is conserved among diverse species ranging from bacteria to mammals and structures form a similar fold (see <PDB:1IAT>) [4,5], comprised of two subdomains that each form an α-β-α sandwich, with the active site located in the cleft between the subdomains and on the dimer interface. A glutamate and a lysine residue as well as a histidine from the other protomer in the dimer are implicated in the catalytic mechanism. The structure resembles that of the SIS domain (see <PDOC51464>).
As signature patterns for this enzyme we selected two conserved regions, the first region is located in the central section of PGI, while the second one is located in its C-terminal section. We also developed a profile that covers the entire PGI.Last update:
September 2009 / Text revised; profile added.
PROSITE methods (with tools and information) covered by this documentation:
|1||Authors||Achari A. Marshall S.E. Muirhead H. Palmieri R.H. Noltmann E.A.|
|Source||Philos. Trans. R. Soc. Lond., B, Biol. Sci. 293:145-157(1981).|
|2||Authors||Smith M.W. Doolittle R.F.|
|Title||Anomalous phylogeny involving the enzyme glucose-6-phosphate isomerase.|
|Source||J. Mol. Evol. 34:544-545(1992).|
|3||Authors||Faik P. Walker J.I.H. Redmill A.A.M. Morgan M.J.|
|Title||Mouse glucose-6-phosphate isomerase and neuroleukin have identical 3' sequences.|
|4||Authors||Read J. Pearce J. Li X. Muirhead H. Chirgwin J. Davies C.|
|Title||The crystal structure of human phosphoglucose isomerase at 1.6 A resolution: implications for catalytic mechanism, cytokine activity and haemolytic anaemia.|
|Source||J. Mol. Biol. 309:447-463(2001).|
|5||Authors||Yamamoto H. Miwa H. Kunishima N.|
|Title||Crystal structure of glucose-6-phosphate isomerase from Thermus thermophilus HB8 showing a snapshot of active dimeric state.|
|Source||J. Mol. Biol. 382:747-762(2008).|