Tryptophan Hydroxylase Products

Description

Tryptophan hydroxylase (TPH) is a 51 kDa, 444 amino acid (aa) enzyme that belongs to the pterin-dependent, aromatic amino-acid hydroxylase family. It is found in peripheral tissues and pineal tissues, and catalyzes the rate-limiting step in serotonin generation from L‑tryptophan. The molecule contains two domains, an N-terminal regulatory domain (aa 1-110) and a C-terminal catalytic domain (aa 111-444) that contains an iron atom. TPH is constitutively active but unstable. Phosphorylation by PKA at S58 stabilizes the enzyme and increases its activity by 25%. This action is complemented by 14-3-3 proteins that physically interact with phosphorylated TPH to increase both its stability and activity by another 15% to 45% of baseline. Binding of the acidic carboxyterminus of 14-3-3 with the regulatory region of TPH also blocks phosphatase activity directed towards TPH, prolonging its activity. One splice variant of TPH is known. It occurs at the extreme C‑terminus where there is a 29 aa substitution for the last seven amino acids. This may generate a more stable enzyme.

Bioinformatics

Alternate Names

TPH TPH1 Tryptophan Hydroxylase