Enzymes
| UniProtKB help_outline | 12,795 proteins |
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- Name help_outline 2-oxoglutarate Identifier CHEBI:16810 (Beilstein: 3664503; CAS: 64-15-3) help_outline Charge -2 Formula C5H4O5 InChIKeyhelp_outline KPGXRSRHYNQIFN-UHFFFAOYSA-L SMILEShelp_outline [O-]C(=O)CCC(=O)C([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 418 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,176 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline isochorismate Identifier CHEBI:29780 (Beilstein: 8334070) help_outline Charge -2 Formula C10H8O6 InChIKeyhelp_outline NTGWPRCCOQCMGE-YUMQZZPRSA-L SMILEShelp_outline O[C@@H]1[C@@H](OC(=C)C([O-])=O)C=CC=C1C([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 5 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline 5-enolpyruvoyl-6-hydroxy-2-succinyl-cyclohex-3-ene-1-carboxylate Identifier CHEBI:58818 (Beilstein: 11278469) help_outline Charge -3 Formula C14H13O9 InChIKeyhelp_outline XYCATPIYKOARSZ-OAIFWDMCSA-K SMILEShelp_outline O[C@@H]1[C@@H](OC(=C)C([O-])=O)C=C[C@@H]([C@H]1C([O-])=O)C(=O)CCC([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 2 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline CO2 Identifier CHEBI:16526 (Beilstein: 1900390; CAS: 124-38-9) help_outline Charge 0 Formula CO2 InChIKeyhelp_outline CURLTUGMZLYLDI-UHFFFAOYSA-N SMILEShelp_outline O=C=O 2D coordinates Mol file for the small molecule Search links Involved in 980 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:25593 | RHEA:25594 | RHEA:25595 | RHEA:25596 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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Menaquinone biosynthesis in Escherichia coli: identification of 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylate as a novel intermediate and re-evaluation of MenD activity.
Jiang M., Cao Y., Guo Z.-F., Chen M., Chen X., Guo Z.
Menaquinone is an electron carrier in the respiratory chain of Escherichia coli during anaerobic growth. Its biosynthesis involves (1R,6R)-2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylic acid (SHCHC) as an intermediate, which is believed to be derived from isochorismate and 2-ketoglutarate by ... >> More
Menaquinone is an electron carrier in the respiratory chain of Escherichia coli during anaerobic growth. Its biosynthesis involves (1R,6R)-2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylic acid (SHCHC) as an intermediate, which is believed to be derived from isochorismate and 2-ketoglutarate by one of the biosynthetic enzymes-MenD. However, we found that the genuine MenD product is 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylic acid (SEPHCHC), rather than SHCHC. This is supported by the following findings: (i) isochorismate consumption and SHCHC formation are not synchronized in the enzymic reaction, (ii) the rate of SHCHC formation is independent of the enzyme concentration, (iii) SHCHC is not formed in weakly acidic or neutral solutions in which the isochorismate substrate is readily consumed by MenD, and (iv) the MenD turnover product, formed under conditions disabling SHCHC formation, possesses spectroscopic characteristics consistent with the structure of SEPHCHC and spontaneously undergoes 2,5-elimination to form SHCHC and pyruvate in weakly basic solutions. Two properties of the intermediate, ultraviolet transparency and chemical instability, provide a rationale for the fact that SHCHC has been consistently mistaken as the MenD product. In accordance with these findings, MenD was rediscovered to be a highly efficient enzyme with a high second-order rate constant and should be renamed SEPHCHC synthase. Intriguingly, the enzymatic activity responsible for conversion of SEPHCHC into SHCHC appears not to associate with any of the known enzymes in menaquinone biosynthesis but is present in the crude extract of E. coli K12, suggesting that a genuine SHCHC synthase remains to be identified to fully elucidate the ubiquitous biosynthetic pathway. << Less