Amino Acids, Proteins and Porphyrins
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.|
- Thiamine has a central role in energy-yielding metabolism and especially the metabolism of carbohydrates.
- 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.
- The oxidative decarboxylation of pyruvate and α-ketoglutarateplaya key role in energy metabolism of most cells.
- In thiamine deficiency, the activity of these two dehydrogenase reaction is decreased, resulting in a decrease production of ATP