Enzymes
UniProtKB help_outline | 4,284 proteins |
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- Name help_outline D-threo-isocitrate Identifier CHEBI:15562 Charge -3 Formula C6H5O7 InChIKeyhelp_outline ODBLHEXUDAPZAU-ZAFYKAAXSA-K SMILEShelp_outline O[C@H]([C@H](CC([O-])=O)C([O-])=O)C([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 9 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline NAD+ Identifier CHEBI:57540 (Beilstein: 3868403) help_outline Charge -1 Formula C21H26N7O14P2 InChIKeyhelp_outline BAWFJGJZGIEFAR-NNYOXOHSSA-M SMILEShelp_outline NC(=O)c1ccc[n+](c1)[C@@H]1O[C@H](COP([O-])(=O)OP([O-])(=O)OC[C@H]2O[C@H]([C@H](O)[C@@H]2O)n2cnc3c(N)ncnc23)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 1,190 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline 2-oxoglutarate Identifier CHEBI:16810 (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 426 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline CO2 Identifier CHEBI:16526 (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 1,006 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline NADH Identifier CHEBI:57945 (Beilstein: 3869564) help_outline Charge -2 Formula C21H27N7O14P2 InChIKeyhelp_outline BOPGDPNILDQYTO-NNYOXOHSSA-L SMILEShelp_outline NC(=O)C1=CN(C=CC1)[C@@H]1O[C@H](COP([O-])(=O)OP([O-])(=O)OC[C@H]2O[C@H]([C@H](O)[C@@H]2O)n2cnc3c(N)ncnc23)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 1,120 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
RHEA:23632 | RHEA:23633 | RHEA:23634 | RHEA:23635 | |
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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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Bifunctional isocitrate-homoisocitrate dehydrogenase: a missing link in the evolution of beta-decarboxylating dehydrogenase.
Miyazaki K.
Beta-decarboxylating dehydrogenases comprise 3-isopropylmalate dehydrogenase, isocitrate dehydrogenase, and homoisocitrate dehydrogenase. They share a high degree of amino acid sequence identity and occupy equivalent positions in the amino acid biosynthetic pathways for leucine, glutamate, and lys ... >> More
Beta-decarboxylating dehydrogenases comprise 3-isopropylmalate dehydrogenase, isocitrate dehydrogenase, and homoisocitrate dehydrogenase. They share a high degree of amino acid sequence identity and occupy equivalent positions in the amino acid biosynthetic pathways for leucine, glutamate, and lysine, respectively. Therefore, not only the enzymes but also the whole pathways should have evolved from a common ancestral pathway. In Pyrococcus horikoshii, only one pathway of the three has been identified in the genomic sequence, and PH1722 is the sole beta-decarboxylating dehydrogenase gene. The organism does not require leucine, glutamate, or lysine for growth; the single pathway might play multiple (i.e., ancestral) roles in amino acid biosynthesis. The PH1722 gene was cloned and expressed in Escherichia coli and the substrate specificity of the recombinant enzyme was investigated. It exhibited activities on isocitrate and homoisocitrate at near equal efficiency, but not on 3-isopropylmalate. PH1722 is thus a novel, bifunctional beta-decarboxylating dehydrogenase, which likely plays a dual role in glutamate and lysine biosynthesis in vivo. << Less
Biochem. Biophys. Res. Commun. 331:341-346(2005) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.
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Evaluation by mutagenesis of the importance of 3 arginines in alpha, beta, and gamma subunits of human NAD-dependent isocitrate dehydrogenase.
Soundar S., Park J.H., Huh T.L., Colman R.F.
Mammalian NAD-dependent isocitrate dehydrogenase is an allosteric enzyme, activated by ADP and composed of 3 distinct subunits in the ratio 2alpha:1beta:1gamma. Based on the crystal structure of NADP-dependent isocitrate dehydrogenases from Escherichia coli, Bacillus subtilis, and pig heart, and a ... >> More
Mammalian NAD-dependent isocitrate dehydrogenase is an allosteric enzyme, activated by ADP and composed of 3 distinct subunits in the ratio 2alpha:1beta:1gamma. Based on the crystal structure of NADP-dependent isocitrate dehydrogenases from Escherichia coli, Bacillus subtilis, and pig heart, and a comparison of their amino acid sequences, alpha-Arg88, beta-Arg99, and gamma-Arg97 of human NAD-dependent isocitrate dehydrogenase were chosen as candidates for mutagenesis to test their roles in catalytic activity and ADP activation. A plasmid harboring cDNA that encodes alpha, beta, and gamma subunits of the human isocitrate dehydrogenase (Kim, Y. O., Koh, H. J., Kim, S. H., Jo, S. H., Huh, J. W., Jeong, K. S., Lee, I. J., Song, B. J., and Huh, T. L. (1999) J. Biol. Chem. 274, 36866-36875) was used to express the enzyme in isocitrate dehydrogenase-deficient E. coli. Wild type (WT) and mutant enzymes (each containing 2 normal subunits plus a mutant subunit with alpha-R88Q, beta-R99Q, or gamma-R97Q) were purified to homogeneity yielding enzymes with 2alpha:1beta:1gamma subunit composition and a native molecular mass of 315 kDa. Specific activities of 22, 14, and 2 micromol of NADH/min/mg were measured, respectively, for WT, beta-R99Q, and gamma-R97Q enzymes. In contrast, mutant enzymes with normal beta and gamma subunits and alpha-R88Q mutant subunit has no detectable activity, demonstrating that, although beta-Arg99 and gamma-Arg97 contribute to activity, alpha-Arg88 is essential for catalysis. For WT enzyme, the Km for isocitrate is 2.2 mm, decreasing to 0.3 mm with added ADP. In contrast, for beta-R99Q and gamma-R97Q enzymes, the Km for isocitrate is the same in the absence or presence of ADP, although all the enzymes bind ADP. These results suggest that beta-Arg99 and gamma-Arg97 are needed for normal ADP activation. In addition, the gamma-R97Q enzyme has a Km for NAD 10 times that of WT enzyme. This study indicates that a normal alpha subunit is required for catalytic activity and alpha-Arg88 likely participates in the isocitrate site, whereas the beta and gamma subunits have roles in the nucleotide functions of this allosteric enzyme. << Less