histidine

noun Biochemistry.

1. an essential amino acid, C3H3N2CH2CH(NH2)COOH, that is a constituent of proteins and is important as the iron-binding site in hemoglobin. Abbreviation: His; Symbol: H

noun

1. a nonessential amino acid that occurs in most proteins: a precursor of histamine

n.

complex amino acid, 1896, from German histidin; see histo- + chemical suffix -idine.

n.

1. An amino acid that is essential for tissue growth and repair.

1. An amino acid that is essential for children but not for adults. Chemical formula: C6H9N3O2.