Editing Maturation promoting factor (section)

== Structure ==
MPF is composed of two subunits: 
* [[Cyclin-dependent kinase 1]] (CDK1), the cyclin-dependent kinase subunit. It uses [[Adenosine triphosphate|ATP]] to phosphorylate specific [[serine]] and [[threonine]] residues of target proteins. 
* [[Cyclin]], a regulatory subunit. The cyclins are necessary for the kinase subunit to function with the appropriate substrate. The mitotic cyclins can be grouped as cyclins A & B. These cyclins have a nine residue sequence in the N-terminal region called the “destruction box”, which can be recognized by the ubiquitin ligase enzyme which destroys the cyclins when appropriate.