Cloned (Comment) | Organism |
---|---|
gene GK1898, recombinant expression in Escherichia coli strain BL21(DE3) | Geobacillus kaustophilus |
Protein Variants | Comment | Organism |
---|---|---|
additional information | thermophilic myo-inositol 2-dehydrogenase (IDH) and scyllo-inositol 2-dehydrogenase (SIDH, EC 1.1.1.370) from Geobacillus kaustophilus are co-expressed in Escherichia coli strain BL21(DE3). The Escherichia coli cells containing the two enzymes are permeabilized by heat treatment (heat treatment at 70°C for 20 min for cell permeabilization) as whole-cell catalysts to convert myo-inositol (MI) to scyllo-inositol (SI). After condition optimizations about permeabilized temperature, reaction temperature, and initial MI concentration, about 82 g/l of SI is produced from 250 g/l of MI within 24 h without any cofactor supplementation. The whole-cell catalytic pathway for SI synthesis is initiated by oxidation of MI to scyllo-inosose catalyzed by cofactor NAD+-dependent IDH. Scyllo-inosose is subsequently reduced to SI by SIDH in the presence of NADH. Recycling of NAD+/NADH is achieved in the whole pathway. The specific activity of SIDH is lower than that of IDH, so SIDH is the rate-limiting step in the two-step cascade reaction. The optimal pH of SIDH is 7.0 and IDH does not become the rate-limited enzyme at pH 7.0. The optimal reaction temperature for SI production is set at 60°C, instabilty and loss of activity at 75°C and above. Method development, overview | Geobacillus kaustophilus |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
myo-inositol + NAD+ | Geobacillus kaustophilus | - |
2,4,6/3,5-pentahydroxycyclohexanone + NADH + H+ | - |
r |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Geobacillus kaustophilus | Q5KYQ3 | - |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
myo-inositol + NAD+ | - |
Geobacillus kaustophilus | 2,4,6/3,5-pentahydroxycyclohexanone + NADH + H+ | - |
r |
Synonyms | Comment | Organism |
---|---|---|
GK1898 | - |
Geobacillus kaustophilus |
IDH | - |
Geobacillus kaustophilus |
myo-inositol 2-dehydrogenase | - |
Geobacillus kaustophilus |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
55 | 75 | assay at | Geobacillus kaustophilus |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
7 | - |
assay at | Geobacillus kaustophilus |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
NAD+ | - |
Geobacillus kaustophilus | |
NADH | - |
Geobacillus kaustophilus |