Methane monooxygenase

Methane monooxygenase, or MMO, is an enzyme capable of oxidizing the C-H bond in methane as well as other alkanes. Methane monooxygenase belongs to the class of oxidoreductase enzymes (EC1.14.13.25).
There are two well-studied forms of MMO: the soluble form (sMMO) and the particulate form (pMMO). The active site in sMMO contains a di-iron center bridged by an oxygen atom (Fe-O-Fe), whereas the active site in pMMO utilizes copper, although some propose that pMMO also uses iron. Structures of both proteins have been determined by X-ray crystallography; however, the location and mechanism of the active site in pMMO is still poorly understood and is an area of active research.