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Biochemistry

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Amino Acids, Proteins and Porphyrins

Question
26 out of 36
 

True about function of Thiamine is: (AIIMS Nov 2008)



A It is required for the process of transamination

B It is cofactor in oxidative reduction
C It is coenzyme for transketolase
D it is coenzyme for pyruvate dehydrogenase and α keto dehydrogenase.

Ans. D It is coenzyme for pyruvate dehydrogenase and a keto dehydrogenase.[Ref: Harper 26/E. p 488]
  1. Thiamine has a central role in energy-yielding metabolism and especially the metabolism of carbohydrates.
  2. Thiamine diphosphate is the coenzyme for:

i. 3 multi enzyme complexes that catalyzes oxidative decarboxylation reactions.

ii. Pyruvate dehydrogenase complex (catalyzes oxidative decarboxylation of pyruvate to acetyl-Co A)

iii. α-ketoglutarate dehydrogenase in the citric acid cycle and

iv. Branched chain keto-acid dehydrogenase involved in the metabolism of leucine, isoleucine and valine.

Transketolase, in the pentose phosphate pathway.

  1. The oxidative decarboxylation of pyruvate and α-ketoglutarateplaya key role in energy metabolism of most cells.
  2. In thiamine deficiency, the activity of these two dehydrogenase reaction is decreased, resulting in a decrease production of ATP

Amino Acids, Proteins and Porphyrins Flashcard List

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