Simple and rapid purification of tryptophan 5-monooxygenase from rabbit brain by affinity chromatography

A simple and rapid method for isolating tryptophan 5-monooxygenase [L-tryptophan, tetrahydropteridine:oxygen oxidoreductase (5-hydroxylating), EC 1.14.16.4] was reported. The method involves adsorption on calcium phosphate gel and affinity chromatography on agarose coupled with dimethyltetrahydropteridine. Tryptophan 5-monooxygenase was purified 1,100-fold from a rabbit brain extract to a specific activity of 15.9 nmol/min.mg, which is far higher than that of the highly purified preparation reported by Tong and Kaufman ((1975) J. Biol. Chem. 250, 4152-4158). It was also demonstrated that this method was applicable to the purification of rat brain tryptophan 5-monooxygenase.