Reactome | TSTA3 dimer epimerises GDP-DHDMan to GDP-KDGal

TSTA3 dimer epimerises GDP-DHDMan to GDP-KDGal

Stable Identifier

R-HSA-6787623

Type

Reaction [transition]

Species

Homo sapiens

Compartment

cytosol

Locations in the PathwayBrowser

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Metabolism of proteins (Homo sapiens)

- Post-translational protein modification (Homo sapiens)
  - Asparagine N-linked glycosylation (Homo sapiens)
    - Biosynthesis of the N-glycan precursor (dolichol lipid-linked oligosaccharide, LLO) and transfer to a nascent protein (Homo sapiens)
      - Synthesis of substrates in N-glycan biosythesis (Homo sapiens)
        
        GDP-fucose biosynthesis (Homo sapiens)
        
        TSTA3 dimer epimerises GDP-DHDMan to GDP-KDGal (Homo sapiens)

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TSTA3 dimer epimerises GDP-DHDMan to GDP-KDGal

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The de novo synthesis pathway for GDP-L-fucose is a two step pathway starting from GDP-mannose. In the second step, GDP-4-dehydro-6-deoxy-alpha-D-mannose (GDP-DHDMan) is epimerised and reduced to GDP-L-fucose (GDP-Fuc). The cytosolic enzyme GDP-L-fucose synthase (TSTA3, aka FX) appears to have both epimerase and reductase activities and functions as a homodimer (Tonetti et al. 1996, Zhou et al. 2013). In the first stage, the hydroxyl group at C-3 and the methyl group at C-5 of the mannose ring of GDP-DHDMan are epimerised to GDP-4-keto-6-deoxygalactose (GDP-KDGal).

Literature References

PubMed ID	Title	Journal	Year
8910301	Synthesis of GDP-L-fucose by the human FX protein Tonetti, M, Sturla, L, Bisso, A, Benatti, U, De Flora, A	J. Biol. Chem.	1996
23774504	The crystal structure of human GDP-L-fucose synthase Zhou, H, Sun, L, Li, J, Xu, C, Yu, F, Liu, Y, Ji, C, He, J	Acta Biochim. Biophys. Sin. (Shanghai)	2013