Tryptophan 5-hydroxylase in rat intestine.
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.
D006916:5-Hydroxytryptophan / Q000096:biosynthesis; D000818:Animals; D002852:Chromatography, Ion Exchange; D002854:Chromatography, Paper; D002855:Chromatography, Thin Layer; D006897:Hydroxyindoleacetic Acid / Q000096:biosynthesis; D007421:Intestine, Small / Q000033:anatomy & histology / Q000187:drug effects / Q000201:enzymology*; D007501:Iron; D008297:Male; D006899:Mixed Function Oxygenases / Q000302:isolation & purification*; D011621:Pteridines; D051381:Rats; D012663:Semicarbazides / Q000494:pharmacology; D012701:Serotonin / Q000096:biosynthesis; D013056:Spectrophotometry, Ultraviolet; D014365:Tryptophan Hydroxylase / Q000302:isolation & purification / Q000378:metabolism
D011621:Pteridines; D012663:Semicarbazides; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D006916:5-Hydroxytryptophan; D007501:Iron; D006899:Mixed Function Oxygenases; D014365:Tryptophan Hydroxylase