Pyruvate Dehydrogenase Complex

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Pyruvate Dehydrogenase Complex is a multi enzyme complex which catalyzes the conversion of pyruvate to acetyl-CoA and CO2. It is important in metabolism as it is the linking step between glycolysis and the citric acid cycle. The complex consists of 3 enzymes;

The enzymes form a channel in the mitrochondrial matrix, passing the reaction intermediates directly from one enzyme to the next. This increases the efficiecy of the enzmes as the intermediate substances are unstable, therefore having the enzymes close together allows for maximum production of acetyl-CoA.

Beriberi

Pyruvate dehydrogenase requires vitamins do be able to convert pyruvate into acetyl Coenzyme A. Vitamin B1 (also called thiamine) is one of the main vitamins needed. It acts as a precursor to the cofactor thiamine pyrophosphate. This cofactor is a prosthetic group for pyruvate dehydrogenase.  Lack of thiamine is common in meat-less diets, which can result in thiamine deficiency and ultimately Beriberi (extreme weakness). Thiamine is found in grains husks and meat. However only brown rice contents high contents of thiamine, therefore populations that eat polished rice or rice soaked in water can have serious health problems. The lack of thiamine, results in a reduction of pyruvate converted to acetyl CoA. The disease results in a loss of appetite, lassitude, numbness of limbs and extremities and atrophy[1]

References

  1. Stryer, L., Berg, J. T. and Tymoczko, J. L. (2011) Stryer biochemistry. 7th edn. Basingstoke: Freeman, Basingstoke.
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