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Dr. Pimchai Chaiyen's Laboratory
: Current systems |
Flavin-dependent enzymes
: OXIDASE
5)
Pyranose 2-oxidase (P2O)
P2O catalyzes the oxidation of pyranose at the C2-position to yield the corresponding 2-keto-sugar. This enzyme has been found to use a wide variety of sugars as substrates, with D-glucose as the best one (reaction of D-glucose and P2O is shown). The reaction catalyzed by pyranose oxidase (P2O) is regarded as one of the most useful types for carbohydrate oxidation because the C2-position of the pyranose ring is oxidized, resulting in a 2-keto-sugar (Figure 2) that can be used in chiral syntheses of rare sugars.
Up to now, P2O has been only one flavoenzyme oxidase in which C4a-hydroxyflavin is detected during natural turnovers (Sucharitakul et al., 2008). We have shown that His548 acts as a catalytic base to abstract a hydroxyl group proton to generate alkoxide prior to the hydride transfer (Wongnate et al., 2011; Sucharitakul 2010). Using a specific labeling technique, we have shown that the breakage of flavin N5-H bond is a major step which controls the overall process of H2O2 elimination from C4a-hydroperoxyflavin (Sucharitakul et al., 2011)
Wongnate et al., ChemBioChem, 2011; Sucharitakul et al., Biochemistry, 2010
Current Project
- Oxygen reactivity of P2O
- Engineering P2O for synthesis of rare-sugars
Investigator:
Thanyaporn Wongnate and Chatchadaporn Pinthong
6)
Alpha-glycerophosphate oxidase (GlpO)
Alpha-glycerophosphate oxidase (GlpO) catalyzes the oxidation of glycerol 3-phosphate into dihydroxyacetone phosphate and H2O2. The enzyme has been shown to be a virulent factor for Mycoplasma pneumoniae.
Current project:
-Reaction mechanism of GlpO
Investigators:
Somchart Maenpuen
7)
Pyranose Dehydrogenase
Pyranose dehydrogenase (PDH) is commonly found in mycelia of litter-decomposing basidiomycete. PDH is a glycosylated monomeric enzyme containing FAD as a cofactor, and catalyzes the oxidation of numerous monosaccharides and oligosaccharides into keto-sugars with broad substrate specificity. PDH can be used in biofuel cell applications.
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