Tryptophan hydroxylase. Purification and some properties of the enzyme from rabbit hindbrain

Tryptophan hydroxylase from rabbit hindbrain has been extensively purified. It is estimated that the enzyme is between 85 and 90% pure and has a molecular weight of 230, 000. Sodium dodecyl sulfate gel electrophoresis shows that the enzyme is composed of two subunits very close in molecular weight (57, 500 and 60, 900). The substrate specificity and the reaction stoichiometry catalyzed by the enzyme in the presence of 6, 7-dimethyltetrahydropterin, 6-methyltetrahydropterin, and tetrahydrobiopterin have been determined. The effect of some natural occurring phospholipids on the purified enzyme was investigated.