Activating Compound | Comment | Organism | Structure |
---|---|---|---|
ADP | activates. Michaelis-Menten constant for DL-isocitrate is lowered 3.5-fold in the wild-type IDH. The substitution of asparagine for aspartate in alpha-mutant enzyme D181N, beta-subunit mutant enzyme D192N, and gamma-subunit mutant enzyme D190N abolishes this allosteric effect of ADP on Km | Homo sapiens |
Protein Variants | Comment | Organism |
---|---|---|
D181N | mutation in the alpha-subunit exhibits a 2000fold decrease in Vmax, with increases of 15fold in the Kms for Mn2+ and NAD+ and a much smaller change in the Km for isocitrate. Mutant enzyme fails to respond to ADP by lowering the Km for isocitrate, although it binds to ADP | Homo sapiens |
D190N | mutation in the gamma-subunit results in 4-5fold decrease in Vmax as compared to wild-type enzyme. The Km-values for NAD+ and for Mn2+ of the mutant enzyme are 19 and 72 times, respectively, that of the wild-type enzyme with a much smaller effect on the Km for isocitrate. Mutant enzyme fails to respond to ADP by lowering the Km for isocitrate, although it binds to ADP | Homo sapiens |
D192N | mutation in the beta-subunit results in 4-5fold decrease in Vmax as compared to wild-type enzyme. The Km-value for NAD+ of the mutant enzyme is 9times that of the normal enzyme with little or no effect on the affinity for Mn2+ or isocitrate. Mutant enzyme fails to respond to ADP by lowering the Km for isocitrate, although it binds to ADP | Homo sapiens |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.08 | - |
NAD+ | pH 7.2, wild-type enzyme | Homo sapiens | |
0.71 | - |
NAD+ | pH 7.2, beta-subunit mutant enzyme D192N | Homo sapiens | |
1.2 | - |
NAD+ | pH 7.2, alpha-subunit mutant enzyme D181N | Homo sapiens | |
1.5 | - |
NAD+ | pH 7.2, gamma-subunit mutant enzyme D190N | Homo sapiens | |
2.4 | - |
isocitrate | pH 7.2, wild-type enzyme | Homo sapiens | |
2.9 | - |
isocitrate | pH 7.2, beta-subunit mutant enzyme D192N | Homo sapiens | |
9.1 | - |
isocitrate | pH 7.2, alpha-subunit mutant enzyme D181N | Homo sapiens | |
13 | - |
isocitrate | pH 7.2, gamma-subunit mutant enzyme D190N | Homo sapiens |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Mn2+ | required. KM-value: 0.067 mM for wild-type enzyme, 1.09 mM for the alpha-subunit mutant D181N, 0.14 mM for the beta-subunit mutant D192N. 4.8 mM for the gamma-subunit mutant D190N | Homo sapiens |
Molecular Weight [Da] | Molecular Weight Maximum [Da] | Comment | Organism |
---|---|---|---|
238000 | - |
gel filtration | Homo sapiens |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Homo sapiens | - |
- |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
isocitrate + NAD+ | - |
Homo sapiens | 2-oxoglutarate + CO2 + NADH + H+ | - |
? |
Subunits | Comment | Organism |
---|---|---|
More | the ratios of the alpha-, beta-, and gamma-subunits of the wild-type and three mutant enzymes all approximate 2:1:1 | Homo sapiens |
Synonyms | Comment | Organism |
---|---|---|
NAD-specific isocitrate dehydrogenase | - |
Homo sapiens |