TH

Description

An enzyme that is located in catecholamine-synthesizing cells and is responsible for the hydroxylation of L-tyrosine to L 3,4-dihydroxyphenylalanine (L-dopa). This is the initial and rate-limiting step in the biosynthetic pathway for catecholamines (dopamine, norepinephrine, and epinephrine). In addition to hydroxylating tyrosine using biopterin as a coenzyme, this enzyme can also hydroxylate phenylalanine to tyrosine. The enzyme is located in the cytosol of catecholamine neurons and has a Km for tyrosine that is in the micromolar range.

Uses

Anti-th antibody produced in rabbit has been used in:

• western blotting (1:1000)
• whole retinal flat-mount immunolabelling (1:500)
• immunofluorescence (2:1000)
• immunohistochemistry (2:1000)

General Description

Tyrosine hydroxylase?(TH) is a cytoplasmic enzyme. The TH gene codes for a monooxygenase.

Biochem/physiol Actions

Cell surface-associated protein is implicated in virulence. Promotes bacterial attachment exclusively to the γ-chain of human fibrinogen. Induces formation of bacterial clumps, which diminish the ability of group IIA phospholipase A2 to cause bacterial phospholipid hydrolysis and killing. Significantly decreases macrophage phagocytosis possibly thanks to the clumps, clumped bacteria being too large to be phagocytosed. Dominant factor responsible for human platelet aggregation, which may be an important mechanism for initiating infective endocarditis. Enhances spleen cell proliferative response in vitro, contributing significantly to the immunostimulatory activity of S.aureus.