[his-ti-deen, -din] /ˈhɪs tɪˌdin, -dɪn/
an essential amino acid, C 3 H 3 N 2 CH 2 CH(NH 2)COOH, that is a constituent of proteins and is important as the iron-binding site in hemoglobin. Symbol: H.
a nonessential amino acid that occurs in most proteins: a precursor of histamine
complex amino acid, 1896, from German histidin; see histo- + chemical suffix -idine.
histidine his·ti·dine (hĭs’tĭ-dēn’, -dĭn)
An amino acid that is essential for tissue growth and repair.
An amino acid that is essential for children but not for adults. Chemical formula: C6H9N3O2.
- Histidine ammonia-lyase
histidine ammonia-lyase n. An enzyme that catalyzes the deamination of histidine to urocanate. Also called histidase, histidinase.
- Histidine decarboxylase
histidine decarboxylase n. An enzyme that catalyzes the decarboxylation of histidine to histamine.
histidinemia his·ti·di·ne·mi·a (hĭs’tĭ-də-nē’mē-ə) n. A hereditary disorder characterized by an elevation of histidine levels in the blood, excretion of histidine in the urine due to deficient histidase activity, and often manifested clinically by mild mental retardation.
histidinuria his·ti·di·nu·ri·a (hĭs’tĭ-də-nur’ē-ə, -nyur’-) n. The excretion of excessive histidine in the urine.