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Your query returned 2 entries. 
Printable version
| EC | 1.1.1.356 | ||||
| Accepted name: | GDP-L-colitose synthase | ||||
| Reaction: | GDP-β-L-colitose + NAD(P)+ = GDP-4-dehydro-3,6-dideoxy-α-D-mannose + NAD(P)H + H+ | ||||
| For diagram of GDP-colitose biosynthesis, click here | |||||
| Glossary: | L-colitose = 3,6-dideoxy-L-xylo-hexopyranose GDP-4-dehydro-3,6-dideoxy-α-D-mannose = GDP-3,6-dideoxy-α-D-threo-hexopyranos-4-ulose |
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| Other name(s): | ColC | ||||
| Systematic name: | GDP-β-L-colitose:NAD(P)+ 4-oxidoreductase (5-epimerizing) | ||||
| Comments: | The enzyme is involved in biosynthesis of L-colitose, a 3,6-dideoxyhexose found in the O-antigen of Gram-negative lipopolysaccharides, where it catalyses the reaction in the reverse direction. The enzyme also performs the NAD(P)H-dependent epimerisation at C-5 of the sugar. The enzyme from Yersinia pseudotuberculosis is Si-specific with respect to NAD(P)H [1]. | ||||
| Links to other databases: | BRENDA, EXPASY, KEGG, MetaCyc | ||||
| References: |
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| EC | 4.2.1.168 | ||||
| Accepted name: | GDP-4-dehydro-6-deoxy-α-D-mannose 3-dehydratase | ||||
| Reaction: | GDP-4-dehydro-α-D-rhamnose + L-glutamate = GDP-4-dehydro-3,6-dideoxy-α-D-mannose + 2-oxoglutarate + NH3 (overall reaction) (1a) GDP-4-dehydro-α-D-rhamnose + L-glutamate = 2-GDP-[(2S,3S,6R)-5-amino-6-methyl-3,6-dihydro-2H-pyran-3-ol] + 2-oxoglutarate + H2O (1b) 2-GDP-[(2S,3S,6R)-5-amino-6-methyl-3,6-dihydro-2H-pyran-3-ol] = 2-GDP-[(2S,3S,6R)-5-imino-6-methyloxan-3-ol] (spontaneous) (1c) GDP-2-[(2S,3S,6R)-5-imino-6-methyloxan-3-ol] + H2O = GDP-4-dehydro-3,6-dideoxy-α-D-mannose + NH3 (spontaneous) |
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| For diagram of GDP-colitose biosynthesis, click here | |||||
| Glossary: | GDP-4-dehydro-α-D-rhamnose = GDP-4-dehydro-6-deoxy-α-D-mannose | ||||
| Other name(s): | colD (gene name) | ||||
| Systematic name: | GDP-4-dehydro-α-D-rhamnose 3-hydro-lyase | ||||
| Comments: | This enzyme, involved in β-L-colitose biosynthesis, is a unique vitamin-B6-dependent enzyme. In the first step of catalysis, the bound pyridoxal phosphate (PLP) cafactor is transaminated to the pyridoxamine 5′-phosphate (PMP) form of vitamin B6, using L-glutamate as the amino group donor. The PMP cofactor then forms a Schiff base with the sugar substrate and the resulting adduct undergoes a 1,4-dehydration to eliminate the 3-OH group. Hydrolysis of the product from the enzyme restores the PLP cofactor and results in the release of an unstable enamine intermediate. This intermediate tautomerizes to form an imine form, which hydrolyses spontaneously, releasing ammonia and forming the final product. | ||||
| Links to other databases: | BRENDA, EXPASY, KEGG, MetaCyc | ||||
| References: |
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