Acetyl CoA

From The School of Biomedical Sciences Wiki
Jump to: navigation, search

Acetyl CoA (acetyl Coenzyme A) is an intermediary involved in the metabolism of glucose, fatty acids and proteins. It is synthesised by the esterfication of acetate and the intermediates in fatty acid biosynthesis [1]

Saturated fatty acids are made from acetyl CoA by two enzymes - acetyl-CoA carboxylase and fatty acid synthase [2] which are found in the cytosol of animal cells.

When pyruvate is produced by glycolysis, it reacts with coenzyme A, forming CO2, NADH and acetyl CoA in the mitochondrial matrix.

In aerobic conditions, the acetyl group of acetyl CoA is almost always oxidised to CO2 via the citric acid cycle (also known as TCA cycle or Kreb cycle), in the mitochondria [3].

Acetyl CoA (Acetyl coenzyme A) is a vital molecule which is needed in metabolism. It's role is to transport 2 carbon atoms, using a high-energy linkage, in biosynthesis of a larger molecule(s)[4]. The rest of the molecule is used as a recognition site for specific enzymes.

Acetyl CoA is used at the start the Kreb's cycle (Citric Cycle) where it is the product of the binding of CoA and pyruvate. This conversion of pyruvate into acetyl CoA consists of three steps: decarboxylation, oxidation, and transfer of the resultant acetyl group to CoA[5]. The acetyl group then is transferred to oxaloacetate which forms citric acid, by the reaction of oxaloacetate with acetyl CoA and water, which then goes through a a series of oxidations to produce energy rich activated carrier molecules. It can also be fed directly into the Kreb's cycle via beta-oxidation, where fatty acids are oxidised into acetyl CoA, the process is carried out in peroxisomes and the resulting Acetyl CoA is expelled into cytosol.

References

  1. Lodish, Berk, Kaiser, Krieger, Scott, Bretscher, Ploegh (2008) Molecular Cell Biology 6th edition 10:430
  2. Lodish, Berk, Kaiser, Krieger, Scott, Bretscher, Ploegh (2008) Molecular Cell Biology 6th edition 10:430
  3. Lodish, Berk, Kaiser, Krieger, Scott, Bretscher, Ploegh (2008) Molecular Cell Biology 6th edition 10:487
  4. Bruce Alberts (2008). Molecular Biology of the Cell. New York: Garland Science. p83-84.
  5. Stryer, L., Berg, J. M. and Tymoczko, J. L., 2002. Biochemistry. 5th ed. : W.H.Freeman and Co Ltd.

Personal tools
Namespaces
Variants
Actions
Navigation
Toolbox