Question

Question 6 2 pts Some amino acids can supply the carbon required for gluconeogenesis by undergoing a reaction catalyzed by an aminotransferase, an enzyme that interconverts amino acids and -keto acids. Aspartate aminotransferase catalyzes the reaction shown below. aspartate + a-ketoglutarate - oxalacetate + glutamate A biochemist studying metabolism feeds 4-[14C]-aspartate (asparatate that has 14C, the radioactive isotope of carbon, at the sidechain carboxylate) to his rats. After sacrificing the rats he is unable to find any +4C in glucose. Which enzyme catalyzes the reaction that is responsible for the fact that no 14C appears in glucose? (Make sure you know the structures of all the compounds mentioned in this question before you attempt to answer it.) o pyruvate carboxylase o pyruvate decarboxylase O PEP carboxykinase o glyceraldehyde 3-P dehydrogenase o fructose 1,6-bisphosphate aldolase

Answer 1

Ans 3 PEP carboxykinase by which oxaloacetate will convert into phosphoenol pyruvate with release of carbon dioxide and energy source in form of one ATP.

So CO2 gas is formed after removing the carboxyl end of aspartate which is actually radiolabelled and hence released CO2 is become radiolabelled not glucose, which is formed from remaining carbon of aspartate molecule.

Hope it's clear ..thanks