pyruvate carboxylase

pyruvate carboxylase n an enzyme that contains biotin as a prosthetic group and in the presence of acetyl coenzyme A catalyzes the fixation of carbon dioxide by pyruvate to form oxalacetate

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py·ru·vate car·box·y·lase (piґroo-vāt kahr-bokґsə-lās) [EC 6.4.1.1] an enzyme of the ligase class that catalyzes the irreversible carboxylation of pyruvate to form oxaloacetate. The enzyme is a mitochondrial protein containing a biotin prosthetic group, requiring Mg²⁺ or Mn²⁺ and acetyl CoA, and occurs in liver but not in muscle. The reaction is necessary for gluconeogenesis from lactate or amino acids forming pyruvate and also provides four-carbon compounds for the tricarboxylic acid cycle. Deficiency of the enzyme, an autosomal recessive trait, causes severe psychomotor retardation and lactic acidosis in infants; there is a particularly severe, rapidly fatal form, in which hyperammonemia, hypercitrullinemia, and hyperlysinemia are also present.