Protein Variants | Comment | Organism |
---|---|---|
E312D | site-directed mutagenesis, the mutant enzyme shows a 260fold decrease in the rate constant for the hydride transfer reaction and did not transfer the hydride ion in a full quantum mechanical tunneling fashion. The overall turnover of the Glu312Asp enzyme at saturating concentrations of 3-hydroxypropyl-trimethylamine and oxygen is predominantly controlled by the hydride transfer reaction that results in the reduction of the enzyme-bound flavin. The kred value with 3-hydroxypropyl-trimethylamine is 20times higher than the value determined with choline as substrate for the Glu312Asp enzyme. The reductive half-reaction can be effectively, but not completely,rescued upon introducing on the substrate the methylenethat is missing from the side chain of residue 312 | Arthrobacter globiformis |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | stopped-flow and steady-state kinetics, and sequential steady-state kinetic mechanism, overview | Arthrobacter globiformis |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
choline + 2 O2 + H2O2 | Arthrobacter globiformis | - |
betaine + 2 H2O2 | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Arthrobacter globiformis | Q7X2H8 | - |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
3-hydroxypropyl-trimethylamine + 2 O2 + H2O2 | - |
Arthrobacter globiformis | ? | - |
? | |
choline + 2 O2 + H2O2 | - |
Arthrobacter globiformis | betaine + 2 H2O2 | - |
? | |
choline + 2 O2 + H2O2 | choline oxidase catalyzes the flavin-mediated, two-step oxidation of choline to glycine betaine with formation of betaine aldehyde as intermediate. Both the oxidation of the alcohol substrate and the aldehyde intermediate require molecular oxygen to accept electrons from the reduced flavin. The reaction of hydride transfer of choline oxidation is rate limiting for the overall turnover of the wild-type and the Glu312Asp enzymes with choline as substrate | Arthrobacter globiformis | betaine + 2 H2O2 | - |
? |
Synonyms | Comment | Organism |
---|---|---|
choline-oxygen 1-oxidoreductase | - |
Arthrobacter globiformis |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
25 | - |
assay at | Arthrobacter globiformis |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
10 | - |
assay at | Arthrobacter globiformis |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
FAD | - |
Arthrobacter globiformis |
General Information | Comment | Organism |
---|---|---|
additional information | in the active site of choline oxidase, Glu312 participates in binding the trimethylammonium group of choline, thereby positioning the alcohol substrate properly for efficient hydride transfer to the enzyme-bound flavin. Glu312 is the only negatively charged residue in the active site of the enzyme | Arthrobacter globiformis |
physiological function | the reaction catalyzed by choline oxidase is of importance due to the trigger of glycine betaine accumulation in the cytoplasm of a number of plants and pathogenic bacteria in response to hyperosmotic and adverse temperature conditions to prevent dehydration and eventual cell death | Arthrobacter globiformis |