Entry M0105    aldehyde oxidase

Previous Step

Step 04

Water deprotonates the thiolate group part of the Mo(V) coordination sphere, causing the elimination of Glu869 from the Mo(V) coordination sphere, and transfer of the second electron from Mo(V) to the acceptor via two iron-sulfur clusters.

It is unknown whether this reaction is reversible or not.

GIF of Reaction Step M0105.stg04

Comment: The overall arrangement of the metal centres in this enzyme is such that they are approximately linear, with Mo and the second 2Fe:2S cluster separated by approx 15 Angstroms, and the two 2Fe:2S clusters separated by approx 12 Angstroms. However, there are direct interactions between the metal centre ligands. The molybdopterin interacts directly with the second 2Fe:2S cluster through a H-bond formed between the N2 atom and the SG of the cluster ligand Cys139. The first and second 2Fe:2S clusters are further linked through a series of covalent and hydrogen bond interactions connecting the two cluster ligands Cys45 and Cys137. These interactions facilitate the electron transfer (which may occur through multiple steps) to an external electron acceptor [1]. It should be noted that the exact atom in the iron sulfur cluster which is accepting the electron is unknown.


Bimolecular Elimination
Electron Transfer

Mechanism Components

Bond Formation
Bond Cleavage
Enzyme-Substrate Bond Cleavage
Bond Order Change
Intermediate Collapse
Intermediate Terminated
Overall Product Formed
Enzyme Regenerated
Metal De-coordination
Cofactor Used
Cofactor Regenerated
Electron Relay

Amino acids involved in the reaction step.

Amino Acid Location of Function Activity Function
Glu869 Side Chain reactant Nucleofuge

Metal Cofactors involved in Step 04

Metal Type Metal Identity Chain Activity Function
iron FES 908 x reactant Electron Relay
One Electron Acceptor
One Electron Donor
iron FES 909 x reactant Electron Relay
One Electron Acceptor
One Electron Donor
molybdenum PCD 921 x reactant One Electron Donor

Reactive Centre

Bonds Formed Bonds Cleaved Bonds Changed in Order Atom Types Involved
The Mo-S bond changes from a single to double bond

View similar reactions in MACiE.