Indole dioxygenase

Indole dioxygenase (E.C. 1.13.11.17 - Indole oxygen 2,3-oxidoreductase (decyclizing). It appears to contain cuprous ions (2). 

An enzymatic pathway for indole degradation was found in A. niger, inducible by the substrate within a 5-h period during growth. Among the enzymes found, anthranilate hydroxylase, N-formylanthranilate deformylase, 2,3-dihydroxybenzoate decarboxylase, and catechol dioxygenase were isolated, and their activities were demonstrated in a cell-free system [342],... 

Figure 13.22 The 02 complex of naphthalene dioxygenase with the substrate analogue indole bound. Asp205 connects the Rieske [2Fe-2S] centre (located in a neighbouring subunit) to the mononuclear iron active site. (From Koehntop et al., 2005. With kind permission of Springer Science and Business Media.)...

This enzyme [EC 1.13.11.42], also referred to as indole-amine-pyrrole 2,3-dioxygenase, catalyzes the reaction of tryptophan with dioxygen to form A-formylkynurenine. Heme participates as a cofactor. Many substituted and unsubstituted indoleamines, including melatonin, act as... 

Dioxygenases that catalyze the cleavage of the indole ring of tryptophan derivatives are known to be the heme proteins, tryptophan 2,3-dioxygenase (tryptophan pyrro-... 

Brady suggested from the experiments with copper chelators190 that indole-amine 2,3-dioxygenase is a copper-containing hemoprotein. On the other hand, Hirata et al. found negligible amounts of copper in their highly purified and active preparation of the enzyme191. ... 

Cobaltn-Schiff base complexes, e.g. Co(salen),567 Co(acacen)568 and cobalt(II) porphyrins,569 e.g. Co(TPP), are effective catalysts for the selective oxygenation of 3-substituted indoles to keto amides (equation 249), a reaction which can be considered as a model for the heme-containing enzyme tryptophan-2,3-dioxygenase (equation 21).66 This reaction has been shown to proceed via a ternary complex, Co-02-indole, with probable structure (175), which is converted into indolenyl hydroperoxide (176). Decomposition of (176) to the keto amide (174) readily occurs in the presence of Co(TPP), presumably via formation of a dioxetane intermediate (177).569,56 Catalytic oxygenolysis of flavonols readily occurs in the presence of Co(salen) and involves a loss of one mole of CO (equation 251).570... 

Figure 2.12 A hypothetical view of compartmentation of indole alkaloid biosynthesis in Catharanthus roseus. Enzymes located with dashed arrows are hypothetical and circles indicate membrane associated enzymes (after Meijer et at, 1 993b). Cl OH, geraniol-1 0-hydroxylase NMT, 5-adenosyl-L-methionine 11 -methoxy 2,16-dihydro-16-hydroxytabersonine N-methyltransferase DAT, acetylcoenzyme A deacetylvindoline 1 7-0-acetyltransferase OHT, 2-oxyglutarate-dependent dioxygenase SSpC, strictosidine-((3)-glucosidase SSS, strictosidine synthase.

The first step of tryptophan catabolism is the oxidative cleavage of the indole ring of L-tryptophan, which is catalyzed by members of the family of pyrrole dioxygenases. A key member of this family, indoleamine-2,3-dioxygenase (IDO, see Fig. 1, EC 1.13.11.17), is expressed in all tissues except in the liver and produces the central metabolite kynurenine (KYN). Two different and competing branches of the pathway then further metabolize KYN the first pathway includes a family of enzymes called kynurenine aminotransferases (KATs), which produce kynurenic acid (KYNA) in a terminal branch. In a second arm, KMO (or kynurenine... 

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