Final answer:
Entacapone (Comtan) and Tolcapone (Tasmar) inhibit the enzyme COMT, resulting in increased dopamine levels in the brain and improved motor function in Parkinson's disease patients.
Step-by-step explanation:
The mechanism of action (MOA) for both Entacapone (Comtan) and Tolcapone (Tasmar) is the inhibition of catechol-O-methyltransferase (COMT), which is an enzyme involved in the breakdown of certain neurotransmitters, including dopamine. By inhibiting COMT, these drugs increase the levels of dopamine in the brain, leading to improved motor function in patients with Parkinson's disease.