PROSITE documentation PDOC00421Phosphoenolpyruvate carboxykinase (GTP) signature
Phosphoenolpyruvate carboxykinase (GTP) (EC 4.1.1.32) (PEPCK) [1] catalyzes the formation of phosphoenolpyruvate by decarboxylation of oxaloacetate while hydrolyzing GTP, a rate limiting step in gluconeogenesis (the biosynthesis of glucose). In vertebrates there are two isozymes: a cytosolic form whose activity is affected by hormones regulating this metabolic process (such as glucagon, or insulin) and a mitochondrial form.
An essential cysteine residue has been proposed [2] to be implicated in the catalytic mechanism; this residue is located in the central part of PEPCK and is in the center of a perfectly conserved region that we use as a signature pattern.
Note:Phosphoenolpyruvate carboxykinase (ATP) (EC 4.1.1.49) an enzyme that catalyzes the same reaction, but using ATP instead of GTP, is not related to the above enzyme (see <PDOC00460>).
Last update:April 2006 / Pattern revised.
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PROSITE method (with tools and information) covered by this documentation:
| 1 | Authors | Weldon S.L. Rando A. Matathias A.S. Hod Y. Kalonick P.A. Savon S. Cook J.S. Hanson R.W. |
| Title | Mitochondrial phosphoenolpyruvate carboxykinase from the chicken. Comparison of the cDNA and protein sequences with the cytosolic isozyme. | |
| Source | J. Biol. Chem. 265:7308-7317(1990). | |
| PubMed ID | 2110163 |
| 2 | Authors | Lewis C.T. Seyer J.M. Carlson G.M. |
| Title | Cysteine 288: an essential hyperreactive thiol of cytosolic phosphoenolpyruvate carboxykinase (GTP). | |
| Source | J. Biol. Chem. 264:27-33(1989). | |
| PubMed ID | 2909519 |
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