Answer:
Please read explanation section.
Step-by-step explanation:
MPF is a protein kinase. It catalyzes the transfer of a phosphate group from ATP to target proteins.
One of the pathways which are stimulated by the MPF is an enzyme that destroys cyclin. This means it stimulates the cyclin pathway. As mitosis gets initiated, the enzyme that breaks down cyclin becomes activated, and levels of cyclin start to be dropping down. The declining levels of cyclin lead to reduced levels of the MPF.