Pyruvate carboxylase

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Pyruvate carboxylase
Identifiers
Symbol	PC
HUGO	[1]
Entrez	5091
OMIM	608786
RefSeq	NM_000920
UniProt	P11498
Other data
EC number	6.4.1.1
Locus	Chr. 11 q11-q13.1

Pyruvate carboxylase is an enzyme of the ligase class (EC 6.4.1.1) that catalyzes the irreversible carboxylation of pyruvate to form oxaloacetate. It is the most important anaplerotic reaction that provides OAA precursor for the TCA during the time of exercise. The enzyme is a mitochondrial protein containing a biotin prosthetic group, requiring magnesium or manganese and acetyl CoA, and occurs in liver but not in muscle. It is an ATP-dependent enzyme. High levels of ADP inhibits the enzyme, while the accumulation of Ac-CoA pushes the reaction forward. Pyruvate carboxylase serves as an example of feedback activation.

[edit] Pathways for Glucose Synthesis (Gluconeogenesis)

It is also the first pathway for the synthesis of PEP from pyruvate. Pyruvate is first converted by pyr carboxylase to oxaloacetate in mitochondrial. During the reaction, one mole of ATP is consumed. The OAA is then decarboxylated and simultaneously phosphorylated, which is catalyzed by PEP carboxykinase to produce PEP in the cytosol. Transport of OAA from mitochondrial to cytosol is mediated by malate/OAA shuttle.

[edit] Clinical significance

A deficiency of this enzyme can cause hypoglycemia - this condition is known as Leigh syndrome.

[edit] See also

• Pyruvate carboxylase deficiency