Glycerol phosphate shuttle

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Glycerol Phosphate Shuttle

The glycerol-3-phosphate shuttle is a mechanism that regenerates NAD+ from NADH, a by-product of glycolysis. Its importance in transporting reducing equivalents is secondary to the malate-aspartate shuttle.

Reaction

In this shuttle, the enzyme called cytoplasmic glycerol-3-phosphate dehydrogenase converts dihydroxyacetone phosphate to glycerol 3-phosphate by oxidizing one molecule of NADH to NAD+ as in the following reaction:[1]

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Reverse path

Glycerol-3-phosphate gets converted back to dihydroxyacetone phosphate by a membrane-bound mitochondrial glycerophosphate dehydrogenase, this time reducing one molecule of enzyme-bound flavin adenine dinucleotide (FAD) to FADH2. FADH2 then reduces coenzyme Q (ubiquinone to ubiquinol) which enters into oxidative phosphorylation.[1] This reaction is irreversible.[2]

Function

The glycerol-3-phosphate shuttle allows the NADH synthesized in the cytosol by glycolysis to contribute to the oxidative phosphorylation pathway in the mitochondria to generate ATP.[1] It has been found in animals, fungi, and plants.[2]

See also

References

  1. 1.0 1.1 1.2 Stryer, Lubert; Berg, Jeremy Mark; Tymoczko, John L. (2007). Biochemistry. San Francisco: W. H. Freeman. ISBN 0-7167-8724-5.
  2. 2.0 2.1 Shen W, Wei Y, Dauk M; et al. (2006). "Involvement of a glycerol-3-phosphate dehydrogenase in modulating the NADH/NAD+ ratio provides evidence of a mitochondrial glycerol-3-phosphate shuttle in Arabidopsis". Plant Cell. 18 (2): 422–41. doi:10.1105/tpc.105.039750. PMC 1356549. PMID 16415206. Unknown parameter |month= ignored (help)

External links


de:Glycerin-3-Phosphat-Shuttle it:Sistema shuttle del glicerolo fosfato


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