Reaction: (1) GDP-α-D-rhamnose + NAD(P)+ = GDP-4-dehydro-α-D-rhamnose + NAD(P)H + H+
(2) GDP-6-deoxy-α-D-talose + NAD(P)+ = GDP-4-dehydro-α-D-rhamnose + NAD(P)H + H+
For diagram click here.
Glossary: GDP-α-D-rhamnose = GDP-6-deoxy-α-D-mannose
GDP-4-dehydro-α-D-rhamnose = GDP-4-dehydro-6-deoxy-α-D-mannose
GDP-6-deoxy-α-D-talose = GDP-α-D-pneumose
Other name(s): GDP-4-keto-6-deoxy-D-mannose reductase; GDP-4-keto-D-rhamnose reductase; guanosine diphosphate-4-keto-D-rhamnose reductase; GDP-6-deoxy-D-mannose:NAD(P)+ 4-oxidoreductase; GDP-6-deoxy-α-D-mannose:NAD(P)+ 4-oxidoreductase
Systematic name: GDP-4-dehydro-α-D-rhamnose:NAD(P)+ 4-oxidoreductase
Comments: The enzyme, which operates in the opposite direction to that shown, forms a mixture of GDP-α-D-rhamnose and its C-4 epimer, GDP-6-deoxy-α-D-talose. cf. EC 1.1.1.281, GDP-4-dehydro-6-deoxy-D-mannose reductase and EC 1.1.1.135, GDP-6-deoxy-D-talose 4-dehydrogenase.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 9075-56-3
References:
1. Barber, G.A. The synthesis of guanosine 5'-diphosphate D-rhamnose by enzymes of a higher plant. Biochim. Biophys. Acta 165 (1968) 68-75. [PMID: 4386238]
2. Winkler, N.W. and Markovitz, A. Guanosine diphosphate-4-keto-D-rhamnose reductase. A non-stereoselective enzyme. J. Biol. Chem. 246 (1971) 5868-5876. [PMID: 4398966]