... sequence of substrate binding in TH [6], the binding of dioxygen prior to the amino acid will promote the placement of tyrosine in the second-ranking, butproductive position.While the unproductive ... BH4 in PAH is shown in red, for BH 4 in TH according to the results of the automated docking in blue, and for BH4 in TH according to the manual docking in the X-ray crystallographic mode in ... inhibition.As the binding sites of catecholamines and BH4overlap in both amino acid hydroxylases, they compete with eachother for obtaining access to the catalytic site. Moreover,bidentate binding of...