Noguchi T, Nishino M, Kido R
Biochem J. 1973 Feb;131(2):375-80. doi: 10.1042/bj1310375.
Tryptophan 5-hydroxylase was partially purified from rat small intestine and characterized. The enzyme activity was mainly localized in the distal one-fourth of the small intestine. The enzyme required Fe(2+), 2-amino-4-hydroxy-6,7-dimethyl-5,6,7,8-tetrahydropteridine and oxygen for full activity. The pH optimum of the reaction was 8.0. The hydroxylation rate of d-tryptophan by the enzyme was one-third that of l-tryptophan. l-Phenylalanine and l-tyrosine could not serve as substrates. The physiological significance of the enzyme is discussed.
色氨酸5-羟化酶从大鼠小肠中部分纯化并进行了特性鉴定。该酶活性主要定位于小肠远端四分之一处。该酶需要Fe(2+)、2-氨基-4-羟基-6,7-二甲基-5,6,7,8-四氢蝶啶和氧气以达到完全活性。反应的最适pH为8.0。该酶对d-色氨酸的羟化速率是l-色氨酸的三分之一。l-苯丙氨酸和l-酪氨酸不能作为底物。文中讨论了该酶的生理意义。