Tyrosine hydrolase, often referred to in the literature as tyrosine hydroxylase (TH), is a critical enzyme in the biosynthesis of catecholamines. It catalyzes the conversion of the amino acid tyrosine into dihydroxyphenylalanine (DOPA), a precursor of neurotransmitters like dopamine, norepinephrine, and epinephrine. This conversion involves the hydroxylation of the aromatic ring of tyrosine, which is the rate-limiting step in the catecholamine synthesis pathway. Given the pivotal role of TH in the synthesis of these neurotransmitters, its activity is tightly regulated and is of substantial biochemical significance.
Inhibitors of tyrosine hydrolase, known as tyrosine hydrolase inhibitors, are compounds that reduce or halt the enzymatic activity of this enzyme. These inhibitors can function through multiple mechanisms, which can include competitive, non-competitive, or uncompetitive inhibition. The structural diversity of TH inhibitors ranges from simple synthetic molecules to intricate natural products. Some inhibitors function by binding directly to the active site of the enzyme, preventing the substrate from accessing it. Others may interact with allosteric sites on the enzyme, triggering conformational changes that diminish its activity.