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 Fe2+, 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.
Research Article| February 01 1973
Tryptophan 5-hydroxylase in rat intestine
Biochem J (1973) 131 (2): 375–380.
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T. Noguchi, M. Nishino, R. Kido; Tryptophan 5-hydroxylase in rat intestine. Biochem J 1 February 1973; 131 (2): 375–380. doi: https://doi.org/10.1042/bj1310375
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