Question

What is the intermediate product between $\alpha$-ketoglutaric acid and succinic acid in Krebs cycle?

• A. Acetyl-Co-A
• B. Oxalo-succinic acid
• C. Fumaric acid
• D. Succinyl-Co-A

Answer 1

The correct option is D Succinyl-Co-A

In reaction 4 of the citric acid cycle, alpha-ketoglutarate loses a carbon dioxide molecule and coenzyme A is added in its place. The decarboxylation occurs with the help of NAD, which is converted to NADH. The resulting molecule is called succinyl-CoA. succinyl-CoA is next converted to succinate by the enzyme succinate thiokinase This is the only example in the TCA cycle of the generation of a high-energy phosphate (either ATP or GTP) at the substrate level.

So, the correct option is, 'Succinyl CoA'.