In: Biology
What role does oxalloacetate play in the TCA cycle? What is the role of oxalloacetate gluconeogenesis?
Oxaloacetate is a four carbon molecule which initiates the first step of citric acid cycle and is regenerated at the end of cycle. Oxaloacetate reacts with acetylCoA to form citrate by citrate synthase and the cycle continues further . Its role is shown in the image attached.
Gluconeogenesis is a pathway which generates glucose from non carbohydrate sources.The initial steps takes place in the mitochondrial matrix, where pyruvate molecules are found. A pyruvate molecule is carboxylated by a pyruvate carboxylase enzyme, activated by a molecule each of ATP and water thereby forming oxaloacetate. NADH reduces oxaloacetate to malate to transport the molecule out of the mitochondria. Once in the cytosol, malate is oxidized to oxaloacetate in cytosol where the rest of reactions take place. Oxaloacetate is further decarboxylated and phosphorylated by phosphoenolpyruvate carboxykinase and becomes 2-phosphoenolpyruvate using guanosine triphosphate (GTP) as phosphate source. Glucose is produced at the end. The steps of gluconeogensis is shown in image attached.