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Entry M0104    1.1.5.2    quinoprotein glucose dehydrogenase

Previous Step

Step 05

The quinone re-oxidises PQQ, the exact mechanism is unclear.

GIF of Reaction Step M0104.stg05


Comment: The PQQ cofactor can be re-oxidised in a single two-electron transfer step. Alternatively, re-oxidation can be achieved in two separate one-electron transfer steps via the free radical semiquinone form. Mechanism unclear.



Mechanisms

Bimolecular Elimination
Hydride Transfer
Bimolecular Nucleophilic Addition

Mechanism Components

Overall Reactant Used
Bond Formation
Bond Cleavage
Bond Order Change
Cofactor Regenerated
Intermediate Terminated
Overall Product Formed
Enzyme Regenerated

Amino acids involved in the reaction step.

Amino Acid Location of Function Activity Function
His144 Side Chain spectator Hydrogen Bond Donor
Asp163 Side Chain spectator Hydrogen Bond Acceptor
Arg228 Side Chain spectator Hydrogen Bond Donor

Organic Cofactors involved in the reaction step

Cofactor Type Cofactor Activity Function
PQQ PQQ1 reactant Hydrogen Bond Donor
Proton Donor
Metal Ligand

Metal Cofactors involved in Step 05

Metal Type Metal Identity Chain Activity Function
calcium CA 1003 A spectator Cofactor Binding
Increase Acidity
Activator

Reactive Centre

Bonds Formed Bonds Cleaved Bonds Changed in Order Atom Types Involved
O-H
O-H
O-H
O-H
The C-C bond changes from a single to double bond
The C-C bond changes from a single to double bond
The C-O bond changes from a single to double bond
The C-O bond changes from a single to double bond
The C-C bond changes from a double to single bond
The C-C bond changes from a double to single bond
The C-O bond changes from a double to single bond
The C-O bond changes from a double to single bond
C
H
O

View similar reactions in MACiE.


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