dopa decarboxylase

the intermediate enzyme in the metabolism of catecholamines from the dietary amino acid tyrosine. Tyrosine is transformed to L-dopa by tyrosine hydroxylase. L-dopa is in turn converted to dopamine by dopa decarboxylase, which also transforms a number of other aromatic amino acids. Dopamine is the final product in dopaminergic neurons; in adrenergic neurons, dopamine is transformed by the enzyme dopamine beta-hydroxylase to norepinephrine and subsequently—in specialized cells in the adrenal medulla and other sites, via the action of the enzyme phenylethanolamine N-methyltransferase—to epinephrine. Also called aromatic L-amino acid decarboxylase.

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Psychology term of the day

March 16th 2025

symptom specificity

a hypothesis stating that people with psychosomatic disorders display abnormal responses to stress in particular physiological systems. According to this hypothesis, a person’s complaints will center around a particular organ (e.g., the heart) and set of related symptoms (e.g., cardiovascular symptoms) rather than involving a variety of complaints about different organs or systems.