The Isocitrate Dehydrogenase (IDH) enzyme structure in Escherichia coli was the first structure to be elucidated and understood.
Since then, the Escherichia coli IDH structure has been used by most researchers to make comparisons to other isocitrate dehydrogenase enzymes.
There is much detailed knowledge about this bacterial enzyme, and it has been found that most isocitrate dehydrogenases are similar in structure and therefore also in function.
This similarity of structure and function gives a reason to believe that the structures are conserved as well as the amino acids.
Therefore, the active sites amongst most prokaryotic isocitrate dehydrogenase enzymes should be conserved as well, which is observed throughout many studies done on prokaryotic enzymes.
Eukaryotic isocitrate dehydrogenase enzymes on the other hand, have not been fully discovered yet.

Each dimer of IDH has two active sites.
Each active site binds a NAD⁺/NADP⁺ molecule and a divalent metal ion (Mg²⁺,Mn²⁺).
In general, each active site has a conserved sequence of amino acids for each specific binding site.
In Desulfotalea psychrophila (DpIDH) and porcine (PcIDH) there are three substrates bound to the active site.

Isocitrate binds within the active site to a conserved sequence of about eight amino acids through hydrogen bonds.
These acids include (may vary in residue but with similar properties) tyrosine, serine, asparagine, arginine, arginine, arginine, tyrosine, and lysine.
Their positions on the backbone vary but they are all within a close range (i.e. Arg131 DpIDH and Arg133 PcIDH, Tyr138 DpIDH and Tyr140 PcIDH).

The metal ion (Mg²⁺, Mn²⁺) binds to three conserved amino acids through hydrogen bonds.
These amino acids include three Aspartate residues.

NAD⁺ and NADP⁺ bind within the active site within four regions with similar properties amongst IDH enzymes.
These regions vary but are around [250–260], [280–290], [300–330], and [365–380].
Again regions vary but the proximity of regions are conserved.
The Isocitrate Dehydrogenase (IDH) enzyme structure in Escherichia coli was the first structure to be elucidated and understood. Since then, the Escherichia coli IDH structure has been used by most researchers to make comparisons to other isocitrate dehydrogenase enzymes. There is much detailed knowledge about this bacterial enzyme, and it has been found that most isocitrate dehydrogenases are similar in structure and therefore also in function. This similarity of structure and function gives a reason to believe that the structures are conserved as well as the amino acids. Therefore, the active sites amongst most prokaryotic isocitrate dehydrogenase enzymes should be conserved as well, which is observed throughout many studies done on prokaryotic enzymes. Eukaryotic isocitrate dehydrogenase enzymes on the other hand, have not been fully discovered yet.
Each dimer of IDH has two active sites. Each active site binds a NAD⁺/NADP⁺ molecule and a divalent metal ion (Mg²⁺,Mn²⁺). In general, each active site has a conserved sequence of amino acids for each specific binding site. In Desulfotalea psychrophila (DpIDH) and porcine (PcIDH) there are three substrates bound to the active site.
Isocitrate binds within the active site to a conserved sequence of about eight amino acids through hydrogen bonds. These acids include (may vary in residue but with similar properties) tyrosine, serine, asparagine, arginine, arginine, arginine, tyrosine, and lysine. Their positions on the backbone vary but they are all within a close range (i.e. Arg131 DpIDH and Arg133 PcIDH, Tyr138 DpIDH and Tyr140 PcIDH).
The metal ion (Mg²⁺, Mn²⁺) binds to three conserved amino acids through hydrogen bonds. These amino acids include three Aspartate residues.
NAD⁺ and NADP⁺ bind within the active site within four regions with similar properties amongst IDH enzymes. These regions vary but are around [250–260], [280–290], [300–330], and [365–380]. Again regions vary but the proximity of regions are conserved.
Isocitrate dehydrogenase