This domain family is found in eukaryotes, and is approximately 30 amino acids in length. There is a single completely conserved residue G that may be functionally important. Tyrosine hydroxylase converts L-tyrosine to L-DOPA in the catecholamine synthesis pathway.

1: Expression of tyrosine hydroxylase in lymphocytes and effect of endogenous catecholamines on lymphocyte function. Qiu YH, Peng YP, Jiang JM, Wang JJ; Neuroimmunomodulation. 2004;11:75-83. PMID:14758053