Glycerol phosphate shuttle

Glycerol Phosphate Shuttle

The glycerol-3-phosphate shuttle is a mechanism that regenerates NAD+ from NADH, a by-product of glycolysis. GPD1 is a gene that codes for proteins responsible for converting dihydroxyacetone phosphate and NADH to glycerol-3-phosphate and NAD+ in order to conduct bodily metabolic processes.[1] The gene GPD2 is responsible for the reverse reaction.[2] 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 1 (GPDH-C) converts dihydroxyacetone phosphate (2) to glycerol 3-phosphate (1) by oxidizing one molecule of NADH to NAD+ as in the following reaction:[3]

Reverse path

Glycerol-3-phosphate gets converted back to dihydroxyacetone phosphate by an inner membrane-bound mitochondrial glycerol-3-phosphate dehydrogenase 2 (GPDH-M), 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.[3] This reaction is irreversible.[4]

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.[3] It has been found in animals, fungi, and plants.[4] Furthermore, on fungi, it was uncertain how glycerol-3-phosphate shuttle affects poisoned fungi. That was until a 2018 study by researchers Yongkai Shi, Huan Wang, Yuxin Yan, Huojuan Cao, Xiaohong Liu, Fucheng Lin, and Jianping Lu, shows that when glycerol-3-phosphate dehydrogenases 1 and 2 are removed from Pyricularia oryzae, it reduces its venom.[5] These enzymes aid in the glycerol-3-phosphate shuttle which is involved in fungal development. Their removal hinders the process.

See also

References

  1. ↑ "GPD1 glycerol-3-phosphate dehydrogenase 1 [Homo sapiens (human)] - Gene - NCBI". www.ncbi.nlm.nih.gov. Retrieved 2021-05-03.
  2. ↑ "GPD2 glycerol-3-phosphate dehydrogenase 2 [Homo sapiens (human)] - Gene - NCBI". www.ncbi.nlm.nih.gov. Retrieved 2021-05-03.
  3. 1 2 3 Stryer, Lubert; Berg, Jeremy Mark; Tymoczko, John L. (2007). Biochemistry. San Francisco: W. H. Freeman. ISBN 978-0-7167-8724-2. Archived from the original on 2007-05-18.
  4. 1 2 Shen W, Wei Y, Dauk M, et al. (February 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.
  5. ↑ Shi, Yongkai; Wang, Huan; Yan, Yuxin; Cao, Huijuan; Liu, Xiaohong; Lin, Fucheng; Lu, Jianping (2018). "Glycerol-3-Phosphate Shuttle Is Involved in Development and Virulence in the Rice Blast Fungus Pyricularia oryzae". Frontiers in Plant Science. 9: 687. doi:10.3389/fpls.2018.00687. ISSN 1664-462X. PMC 5974175. PMID 29875789.


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