Catecholamine biosynthesis pathway enzyme (None commonly used collectively; individual enzymes have abbreviations (e.g., TH for Tyrosine hydroxylase, DDC for DOPA decarboxylase).)

The catecholamine biosynthesis pathway consists of four major enzymes: tyrosine hydroxylase (TH), the rate-limiting enzyme converting tyrosine to L-DOPA; DOPA decarboxylase (DDC), which converts L-DOPA to dopamine; dopamine beta-hydroxylase (DBH), converting dopamine to norepinephrine; and phenylethanolamine N-methyltransferase (PNMT), which methylates norepinephrine to form epinephrine. These enzymes are expressed in catecholaminergic neurons and the adrenal medulla, and their sequential activity regulates production of the neurotransmitters and hormones central to stress response, mood regulation, and autonomic function. Each enzyme is a distinct molecular target, and their dysfunction is associated with diseases such as Parkinson’s disease, phenylketonuria, and adrenal tumors[1][3][4]. Therapeutic targeting usually focuses on individual enzymes rather than the collective pathway.

Other names

Catecholamine pathway enzymesCatecholamine biosynthesis enzymesEnzymes of dopamine, norepinephrine and epinephrine synthesisTyrosine hydroxylase, DOPA decarboxylase, Dopamine beta-hydroxylase, Phenylethanolamine N-methyltransferase (when listed individually)

Enzyme inhibition (reducing catecholamine synthesis, e.g., TH inhibitors for hypertension or pheochromocytoma) Enzyme substrate analogues (e.g., α-methyldopa acts as a false neurotransmitter) Enzyme cofactor modulation (Vitamin B6 for DDC, Vitamin C for DBH, SAM for PNMT).