Catecholamine

Catecholamines are molecules synthesized from tyrosine that contain a catechol group and an amine group. Dopamine, norepinephrine, and epinephrine act as neurotransmitters or hormones.

Tyrosine hydroxylase: An enzyme that converts tyrosine into L-DOPA, the rate-limiting step in catecholamine synthesis. It catalyzes the pathway’s first committed step toward dopamine and the other catecholamines.
Dopamine: A catecholamine that functions as a neurotransmitter and precursor to norepinephrine. It is both a prominent signaling molecule and the branch point for downstream catecholamines.
Parkinson's disease: A progressive neurological disorder marked by degeneration of dopamine-producing neurons and impaired movement. Loss of dopamine signaling motivates treatment with the catecholamine precursor L-DOPA.
Phenylalanine: An essential amino acid that can be converted into tyrosine in the body. Dietary phenylalanine can ultimately supply the tyrosine used for catecholamine synthesis.
Indoleamine: A monoamine containing an indole ring, such as serotonin or melatonin. Indoleamines are another monoamine family but lack catecholamines’ catechol structure.
DOPA decarboxylase: An enzyme that converts L-DOPA into dopamine. It produces dopamine after tyrosine hydroxylase forms L-DOPA.
Norepinephrine: A catecholamine neurotransmitter and hormone involved in arousal and sympathetic signaling. It acts as a neurotransmitter in the brain and a transmitter and hormone in the body.
Pheochromocytoma: A usually adrenal tumor of chromaffin cells that can release excess catecholamines. Excess epinephrine or norepinephrine can produce episodic hypertension and other symptoms.
Dopamine beta-hydroxylase: An enzyme that converts dopamine into norepinephrine inside secretory vesicles. This reaction directs dopamine into norepinephrine production.
Serotonin: A monoamine neurotransmitter derived from tryptophan and commonly classified as an indoleamine. It is often compared with dopamine but belongs to a different chemical family.

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