IUBMB Enzyme Nomenclature


Accepted name: GDP-L-galactose phosphorylase

Reaction: GDP-β-L-galactose + phosphate = β-L-galactose 1-phosphate + GDP

Other name(s): VTC2; VTC5

Systematic name: GDP:α-L-galactose 1-phosphate guanylyltransferase

Comments: The enzyme catalyses a reaction of the Smirnoff-Wheeler pathway, the major route to ascorbate biosynthesis in plants.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:


1. Linster, C.L., Gomez, T.A., Christensen, K.C., Adler, L.N., Young, B.D., Brenner, C. and Clarke, S.G. Arabidopsis VTC2 encodes a GDP-L-galactose phosphorylase, the last unknown enzyme in the Smirnoff-Wheeler pathway to ascorbic acid in plants. J. Biol. Chem. 282 (2007) 18879-18885. [PMID: 17462988]

2. Linster, C.L., Adler, L.N., Webb, K., Christensen, K.C., Brenner, C. and Clarke, S.G. A second GDP-L-galactose phosphorylase in arabidopsis en route to vitamin C. Covalent intermediate and substrate requirements for the conserved reaction. J. Biol. Chem. 283 (2008) 18483-18492. [PMID: 18463094]

3. Dowdle, J., Ishikawa, T., Gatzek, S., Rolinski, S. and Smirnoff, N. Two genes in Arabidopsis thaliana encoding GDP-L-galactose phosphorylase are required for ascorbate biosynthesis and seedling viability. Plant J. 52 (2007) 673-689. [PMID: 17877701]

4. Muller-Moule, P. An expression analysis of the ascorbate biosynthesis enzyme VTC2. Plant Mol. Biol. 68 (2008) 31-41. [PMID: 18516687]

[EC created 2010]

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