Xanthurenate-8-O-beta-D-glucoside
IUPAC 名称
4-hydroxy-8-{[(2S,3S,4S,5R,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy}quinoline-2-carboxylic acid
描述
Xanthurenic acid 8-O-beta-D-glucoside, a fluorescent metabolite, has been isolated from heads of eye-color mutants of Drosophila melanogaster. Only a few mutations cause it to accumulate, viz. cardinal (cd), dark red brown (drb), Henna-recessive (Hnr), purple (pr), Punch2 (Pu2), Punch-Grape (PuGr), and scarlet (st). After purification by ion-exchange chromatography, the spectroscopic, chemical, and enzymatic analyses revealed that it is a novel quinoline derivative. Feeding experiments suggest that this glucoside is synthesized from 3-hydroxykynurenine and that free xanthurenic acid is not a precursor. The results from the analysis for its occurrence in double mutants, together with the fact that xanthurenic acid 8-glucoside share the same precursor as xanthurenic acid and xanthommatin, suggest that xanthurenic acid 8-glucoside formation is closely related to the regulation of the last step in the biosynthesis of xanthommatin.[PMID: 3922986]
Xanthurenic acid 8-glucoside is a side metabolite of the tryptophan-xanthommatin pathway in Drosophila. From 3-hydroxykynurenine, two biosynthetic pathways can be envisaged, one via xanthurenic acid, and another via 3-O-glucoside of 3-hydroxykynurenine. Evidence is presented to show that the synthesis takes place via xanthurenic acid. (a) the Drosophila melanogaster vermilion purple mutant (unable to synthesize 3-hydroxykynurenine) synthesizes xanthurenic acid 8-glucoside when fed with xanthurenic acid; and (b) the activities required for its synthesis via xanthurenic acid have been found (3-hydroxykynurenine transaminase and xanthurenic acid:UDP-glucosyltransferase). This is the first time that a UDP-glucosyltransferase activity that utilizes xanthurenic acid has been demonstrated. The enzyme in crude extracts from Drosophila sordidula shows the following characteristics. (a) It has optimal activity at 35 degrees C at pH 7.1 (in buffer Tris-HCl), and in the presence of a divalent cation (Mg2+ or Mn2+); (b) the activity is inhibited by xanthurenic acid (above 1.5 mM), UDP, D-gluconic acid 1,5-lactone, and Triton X-100; (c) it is localized in both the microsomal and the soluble fractions; (d) the specific activity is two times higher in heads than in bodies; and (e) the activity is enhanced in flies fed with phenobarbital. [HMDB]
异构
OC[C@H]1O[C@@H](OC2=C3N=C(C=C(O)C3=CC=C2)C(O)=O)[C@@H](O)[C@@H](O)[C@H]1O
InChI标识符
InChI=1S/C16H17NO9/c18-5-10-12(20)13(21)14(22)16(26-10)25-9-3-1-2-6-8(19)4-7(15(23)24)17-11(6)9/h1-4,10,12-14,16,18,20-22H,5H2,(H,17,19)(H,23,24)/t10-,12+,13+,14+,16-/m1/s1
键
MYFHOUJDPFBJLH-XGJKELJWSA-N