Glucose oxidase

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Glucose oxidase ( Penicillium amagasakiense )
Mass / length primary structure 587 amino acids
Secondary to quaternary structure Homodimer
Cofactor FAD
Identifier
External IDs
Enzyme classification
EC, category 1.1.3.4 ,  oxidoreductase
Response type Redox reaction
Substrate β-D-glucose + O 2
Products D-glucono-1,5-lactone + H 2 O 2

Glucose oxidase (GOD, and glucose oxidase) is an enzyme that the oxygen -dependent oxidation at the C1 carbon atom of the sugar glucose catalyzed .

The dimeric flavoenzyme converts glucose and oxygen into gluconolactone and hydrogen peroxide . It occurs in fungi such as the white-rot fungus Phanerochaete chrysosporium and the molds Aspergillus niger and Penicillium amagasakiense , but has also been detected in Bombyx mori . The crystal structure of the enzyme from these two fungi was determined by X-ray crystallography. The molecular mass is 120  kDa .

After the glucose has bound to the enzyme, the electron is transferred to the FAD bound to the enzyme , which is reduced to FADH 2 . The gluconolactone is released; it can be hydrolyzed spontaneously or enzymatically to gluconic acid. In a second step, molecular oxygen is added to the isoalloxazine ring system of the FAD and the hydroperoxide is then released as hydrogen peroxide. Molecular oxygen is the natural electron acceptor, but the enzyme can work with a number of artificial acceptors.

The enzyme is of great importance in the determination of glucose with the GOD test . It is also used more often as a model enzyme for electronic mini-enzyme biosensors, where the enzyme is applied to a metal surface and can pass on the electrons of the redox reaction it catalyzes.

Occurrence

Glucose oxidase may be used. a. of course in honey . It is part of the body's own secretions that the bees add to the nectar during transport from the flower to the hive . The transfer of electrons to molecular oxygen catalyzed by glucose oxidase, whereby germicidal or germ-inhibiting hydrogen peroxide is formed, is of great importance for the preservation of honey in the beehive .

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  1. ↑ BRENDA - the comprehensive enzyme information system
  2. ^ Helmut Horn and Cord Lüllmann: "The great honey book - development, extraction, health and marketing", Franckh-Kosmos Stuttgart, 3rd edition 2002, ISBN 978-3-440-10838-3

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