Activating Compound | Comment | Organism | Structure |
---|---|---|---|
fructose 1,6-bisphosphate | assures that the protein forms tetrameric uniformity and serves as an allosteric activator of the enzyme | Geobacillus stearothermophilus |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | Michaelis-Menten kinetic modelling, detailed overview. NADH can bind only to the open-loop apoenzyme, substrate analogue oxamate can bind only to the bsLDH·NADH binary complex in the open-loop conformation, and oxamate binding is followed by closing of the active site loop preventing oxamate unbinding. The open and closed states of the loop are in dynamic equilibrium and interconvert on the submillisecond time scale. This interconversion strongly accelerates with an increase in temperature because of significant enthalpy barriers. Binding of NADH to bsLDH results in minor changes of the loop dynamics and does not shift the open-closed equilibrium, but binding of the oxamate substrate mimic shifts this equilibrium to the closed state. At high excess oxamate concentrations where all active sites are nearly saturated with the substrate mimic, all active site mobile loops are mainly closed, kinetic analysis, overview | Geobacillus stearothermophilus |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
(S)-lactate + NAD+ | Geobacillus stearothermophilus | - |
pyruvate + NADH + H+ | - |
r | |
pyruvate + NADH + H+ | Geobacillus stearothermophilus | - |
(S)-lactate + NAD+ | - |
r |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Geobacillus stearothermophilus | P00344 | i.e. Geobacillus stearothermophilus | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
(S)-lactate + NAD+ | - |
Geobacillus stearothermophilus | pyruvate + NADH + H+ | - |
r | |
additional information | substrate analogue oxamate is isoelectric and isosteric to pyruvate and has binding kinetics very similar to that of pyruvate. As the substrate approaches the catalytic site, a catalytically key surface loop (residues 98-110) closes over the ligand, bringing residue Arg109 into hydrogen bonding contact with ligand, water leaves the pocket, and the pocket geometry rearranges to allow for favorable interactions between the cofactor and the ligand, which facilitates on-enzyme catalysis | Geobacillus stearothermophilus | ? | - |
? | |
pyruvate + NADH + H+ | - |
Geobacillus stearothermophilus | (S)-lactate + NAD+ | - |
r |
Synonyms | Comment | Organism |
---|---|---|
lactate dehydrogenase | - |
Geobacillus stearothermophilus |
LDH | - |
Geobacillus stearothermophilus |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
20 | 40 | assay at | Geobacillus stearothermophilus |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
6 | - |
assay at | Geobacillus stearothermophilus |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
NAD+ | - |
Geobacillus stearothermophilus | |
NADH | kinetic modelling of NADH binding to the enzyme, overview | Geobacillus stearothermophilus |