Question

Entacapone and tolcapone exert their antiparkinsonian effects on which one of the following enzymes?

A. Catechol-O-methyltransferase (COMT)
B. Monoamine oxidase type A
C. Monoamine oxidase type B
D. DOPA decarboxylase
E. Dopamine β-hydroxylase

Answer 1

Entacapone and tolcapone target the enzyme Catechol-O-methyltransferase (COMT) to help manage symptoms of Parkinson's disease by prolonging the effects of dopamine in the brain.

Step-by-step explanation:

Entacapone and tolcapone exert their antiparkinsonian effects by inhibiting the enzyme Catechol-O-methyltransferase (COMT). These medications work by preventing the breakdown of dopamine in the brain, which is a common issue in Parkinson's disease patients suffering from loss of dopaminergic neurons in the substantia nigra. By blocking COMT, these drugs help increase and prolong the effects of L-DOPA, the precursor to dopamine which is another treatment for Parkinson's.