Thiamine pyrophosphate serves as a coenzyme for oxidative decarboxylation reactions central to energy metabolism. All of the following mammalian enzymes require it EXCEPT:

• A Pyruvate dehydrogenase complex
• B Malate dehydrogenase ✓
• C Transketolase
• D Alpha-ketoglutarate dehydrogenase complex

Explanation

Thiamine pyrophosphate is the prosthetic group of three enzymes of energy metabolism: pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase and branched-chain ketoacid dehydrogenase (all alpha-ketoacid decarboxylases), plus transketolase of the hexose monophosphate shunt. Malate dehydrogenase catalyses reversible oxidation of malate to oxaloacetate and uses NAD+ as its coenzyme without any thiamine requirement. Erythrocyte transketolase activity is the functional test used to assess thiamine status.

Reference: Harper's Illustrated Biochemistry, 32nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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