In gluconeogenesis, which enzyme catalyzes the conversion of oxaloacetate to phosphoenolpyruvate?

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Multiple Choice

In gluconeogenesis, which enzyme catalyzes the conversion of oxaloacetate to phosphoenolpyruvate?

The key idea is that gluconeogenesis uses a distinct step to bypass a glycolytic reaction, turning oxaloacetate into phosphoenolpyruvate through a decarboxylation and phosphorylation process. This transformation is carried out by PEP carboxykinase, which removes a CO2 and transfers a phosphate from GTP to form phosphoenolpyruvate. In mammals there are mitochondrial and cytosolic forms, reflecting where oxaloacetate is located and how it’s shuttled for the reaction. The other enzymes do different tasks: pyruvate carboxylase makes oxaloacetate from pyruvate, fructose-1,6-bisphosphatase acts later to remove a phosphate from fructose-1,6-bisphosphate, and glucose-6-phosphatase releases glucose from glucose-6-phosphate.

The key idea is that gluconeogenesis uses a distinct step to bypass a glycolytic reaction, turning oxaloacetate into phosphoenolpyruvate through a decarboxylation and phosphorylation process. This transformation is carried out by PEP carboxykinase, which removes a CO2 and transfers a phosphate from GTP to form phosphoenolpyruvate. In mammals there are mitochondrial and cytosolic forms, reflecting where oxaloacetate is located and how it’s shuttled for the reaction. The other enzymes do different tasks: pyruvate carboxylase makes oxaloacetate from pyruvate, fructose-1,6-bisphosphatase acts later to remove a phosphate from fructose-1,6-bisphosphate, and glucose-6-phosphatase releases glucose from glucose-6-phosphate.

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