Human indolylamine 2,3-dioxygenase. Its tissue distribution, and characterization of the placental enzyme

摘要: The presence of indolylamine 2,3-dioxygenase was examined in human subjects by determining its activity with L-tryptophan as substrate. Enzyme detected various tissues, and relatively high the lung, small intestine placenta. Human 2,3-dioxygenase, partially purified from placenta, had an Mr about 40 000 gel filtration exhibited a single pI 6.9. enzyme required reducing system, ascorbic acid Methylene Blue, for maximal able to oxidize D-tryptophan, 5-hydroxy-L-tryptophan well L-tryptophan, but kinetic studies indicated that best substrate L-tryptophan.