Human mitochondrial phosphoenolpyruvate carboxykinase 2 gene

Kinetic and functional properties of human mitochondrial phosphoenolpyruvate carboxykinase

The cytosolic form of phosphoenolpyruvate carboxykinase (PCK1) plays a regulatory role in gluconeogenesis and glyceroneogenesis. The role of the mitochondrial isoform (PCK2) remains unclear. We report the partial purification and kinetic and functional characterization of human PCK2. Kinetic properties of the enzyme are very similar to those of the cytosolic enzyme. PCK2 has an absolute require...

Phosphoenolpyruvate Cycling via Mitochondrial Phosphoenolpyruvate Carboxykinase Links Anaplerosis and Mitochondrial GTP with Insulin Secretion*

Pancreatic beta-cells couple the oxidation of glucose to the secretion of insulin. Apart from the canonical K(ATP)-dependent glucose-stimulated insulin secretion (GSIS), there are important K(ATP)-independent mechanisms involving both anaplerosis and mitochondrial GTP (mtGTP). How mtGTP that is trapped within the mitochondrial matrix regulates the cytosolic calcium increases that drive GSIS rem...

Multihormonal Regulation of Phosphoenolpyruvate Carboxykinase Gene Transcription

We used a nuclear RNA transcript elongation assay to show that cAMP analogs and dexamethasone cause a selective increase of transcription of the P-enolpyruvate carboxykinase gene in H4IIE hepatoma cells. 8-(4-~hlorophenylthio)-cAMP increased transcription within 5 min and the maximal rate, generally 10-15fold above the basal rate, was attained by 30 min. This increase was of sufficient magnitud...

Inactivation of chicken mitochondrial phosphoenolpyruvate carboxykinase by o-phthalaldehyde.

Chicken liver mitochondrial phosphoenolpyruvate carboxykinase is inactivated by o-phthalaldehyde. The inactivation followed pseudo first-order kinetics, and the second-order rate constant for the inactivation process was 29 M-1 s-1 at pH 7.5 and 25 degrees C. The modified enzyme showed maximal fluorescence at 427 nm upon excitation at 337 nm, consistent with the formation of isoindole derivativ...

PPARg2 Regulates Adipose Expression of the Phosphoenolpyruvate Carboxykinase Gene