Xanthurenic conjugated

Taurine conjugation with bile acids, phenylacetic acid, and indolylacetic acid seems to be a minor process in most species, but in the pigeon and ferret, it occurs extensively. Other infrequently reported conjugations include serine conjugation of xanthurenic acid in rats excretion of quinaldic acid as quinaldylglycyltaurine and quinaldylglycylglycine in the urine of the cat, but not of the rat or rabbit and conversion of furfural to furylacrylie acid in the dog and rabbit, but not in the rat, hen, or human. The dog and... 

Boyland and Williams (B18) loaded 10 normal controls with 10 g DL-tryptophan. In spite of the fact that it is essential to use L-tryptophan in studies of this type and although data on excretion of kynurenic and xanthurenic acids are lacking, at least 5% was recovered as increased kynurenine, 3-hydroxykynurenine, anthranilic acid, and 3-hydroxyan-thranilic acid, free and conjugated. It should be pointed out that in these studies only a low percentage of the ingested dose of tryptophan was found in the form of urinary metabolites. The remainder, approximately 93-94%, of the load could not be recovered. 

K18. Kotake, Y., and Nogami, K., Xanthurenic acid. XIII. EfiFect of 5-hydroxy-anthranilic acid on the formation and conjugating reaction of xanthurenic acid in albino rat. ]. Biochem. (Tokyo) 43, 437-443 (1956). 

Xanthurenic acid if present in unusual amount is also treated as a foreign phenol and excreted in conjugated form (171, 513), though the nature of the conjugating groups has not been established. Xanthurenic acid can probably also be degraded to some extent by an enzyme, xanthurenicase, in liver and kidney (510), but the products have not been identified. 

Fic. 1. Metabolism of tryptophan to serotonin (5-hydroxytryptamine) and niacin. Fyiidoxal phosphate (PLP) dependent reactions are indicated. Reactions not shown which may result in formation of products excreted in urine include the acetylation of liymuenine and 3-hydroxykynurenine, conjugation of anthranilic acid with glycine (to form o-aminohippuric acid) and with glucuronic acid, and the dehydroxylation of kynurenic acid and xanthurenic add to quinaldic add and 8-hydroxyquinaldic add, respectively. 

Trypto- phan Indole- acetate Indole- lactate Indole- pyruvate 5-Hy- droxyin- doleace- tate 3-Hy- droxyky- nurenine Xanthurenic acid Kynurenic 3-Hy-acid droxyky-nurenine- sulfate Acetyl-3-hydroxy-kynure-nine Acetyl ky-nurenine Conjugated xanthurenic acid... 

Disorder Tryptophan (P) pmol/l Tryptophan (U) pmol/ 24 h Indoleace-tate (U) pmol/24 h Indolelac-tate (U) pmol/24 h Indolepy-ruvate (U) pmol/24 h 5-Hydroxy-indoleace-tate (U) pmol/24 h 3-Hydroxy- kynurenine (U) Hmol/24 h Xanthurenic add (U) pmoI/24 h Kynurenic acid (U) pmol/24 h 3 -Hydr oxyky nurenine sulfate, acetyl-3-hy-droxyky n ur enine, acety Iky nurenine, conjugated xanthurenic acid... 

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