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Search The CSA
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Catalytic Site Atlas

CSA LITERATURE entry for 1gal

E.C. nameglucose oxidase
SpeciesAspergillus niger (strain CBS 513.88 / FGSC A1513)
E.C. Number (IntEnz) 1.1.3.4
CSA Homologues of 1gal1cf3,1gpe,1qjn,3fim,
CSA Entries With UniProtID P13006
CSA Entries With EC Number 1.1.3.4
PDBe Entry 1gal
PDBSum Entry 1gal
MACiE Entry 1gal

Literature Report

IntroductionGlucose oxidase is a flavin dependent glycoprotein. The fungal enzyme is a homodimer made up of two identical subunits, each containing one molecule of non-covalently bound FAD. The enzyme catalyses the oxidation of beta-D-glucose, where the FAD cofactor acts as the redox carrier.
MechansimCrystallographic investigations have shown the flavin containing active site to be buried in a deep pocket. The binding of glucose to the free enzyme results in the expulsion of a water molecule and a proton from the active site. In the reduction half reaction, simultaneous hydride and proton transfer from the glucose to the FAD and His516 respectively occurs. In the oxidation half reaction, the reduced coenzyme FADH- is reoxidised hack to FAD by molecule dioxygen which undergoes reduction to hydrogen peroxide in two single electron transfer steps.
The hydride transfer is thought to be regulated by dissociation between Glu412 and His559. The electrostatic interaction between these residues controls the pH and therefore reactivity of the active site, although they are not directly involved in the catalytic mechanism.
Reaction

Catalytic Sites for 1gal

Annotated By Reference To The Literature - Site 1 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
HisA516538macie:sideChainThe residue acts as a general base towards the C1-OH group of the glucose substrate. As the proton is removed, the oxygen partial negative charge drives the hydride transfer to the N5 of FAD resulting in FADH-. A ketone is formed at the C1 of glucose.

Literature References

Notes:
Leskovac V
Glucose oxidase from Aspergillus niger: the mechanism of action with molecular oxygen, quinones, and one-electron acceptors.
Int J Biochem Cell Biol 2005 37 731-750
PubMed: 15694834
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