CVS Practice Test 2025 - Free CVS Practice Questions and Study Guide

The enzyme that converts tyrosine to Dopa is tyrosine hydroxylase. This enzyme catalyzes the hydroxylation of tyrosine to form Dopa (dihydroxyphenylalanine), a crucial step in the biosynthesis of catecholamines, which include neurotransmitters such as dopamine, norepinephrine, and epinephrine. The activity of tyrosine hydroxylase is reliant on the presence of oxygen and tetrahydrobiopterin (BH4) as a cofactor, making it a vital enzyme for the production of these important molecules in the body.

In contrast, phenylalanine hydroxylase is responsible for converting phenylalanine, a precursor of tyrosine, into tyrosine itself and is not directly involved in the conversion of tyrosine to Dopa. Dopa decarboxylase is the enzyme that decarboxylates Dopa to form dopamine, playing a later role in the synthesis pathway. Cyclooxygenase is involved in the conversion of arachidonic acid to prostaglandins and thromboxanes, which is unrelated to the conversion of tyrosine to Dopa. Thus, tyrosine hydroxylase is synonymous with the