PROSITE documentation PDOC00421 [for PROSITE entry PS00505]
Phosphoenolpyruvate carboxykinase (GTP) signature


Phosphoenolpyruvate carboxykinase (GTP) (EC (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.


Phosphoenolpyruvate carboxykinase (ATP) (EC 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.


Technical section

PROSITE method (with tools and information) covered by this documentation:

PEPCK_GTP, PS00505; Phosphoenolpyruvate carboxykinase (GTP) signature  (PATTERN)


1AuthorsWeldon S.L. Rando A. Matathias A.S. Hod Y. Kalonick P.A. Savon S. Cook J.S. Hanson R.W.
TitleMitochondrial phosphoenolpyruvate carboxykinase from the chicken. Comparison of the cDNA and protein sequences with the cytosolic isozyme.
SourceJ. Biol. Chem. 265:7308-7317(1990).
PubMed ID2110163

2AuthorsLewis C.T. Seyer J.M. Carlson G.M.
TitleCysteine 288: an essential hyperreactive thiol of cytosolic phosphoenolpyruvate carboxykinase (GTP).
SourceJ. Biol. Chem. 264:27-33(1989).
PubMed ID2909519

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