Question

Outline the first part of gluconeogenesis,starting in the mitochondria, and ending with PEP

Answer 1

Ans.

The first step of gluconeogenesis is the conversation of pyruvate into phosphoenolpyruvic acid (PEP).This coversion process is catalyzed by the following enzymes; Pyruvate carboxylase, PEP carboxykinase and malate dehydrogenase. Following are the steps involved:

1. First the pyruvate is converted into oxaloacetate with the help of enzyme Pyruvate carboxylase,which is found inside the mitochondria.
2. Since oxaloacetate cannot pass through the mitochondrial membrane, it should be first converted into malate.This is done by the enzyme malate dehydrogenase.The malate then moves out of mitochondrial membrane into the cytoplasm,where it is converted back into oxaloacetate with the help of another malate dehydrogenase.
3. Finally with the help of enzyme PEP carboxykinase, the oxaloacetate is converted into PEP.