Aureusidin

Nakayama, T. Yonekura-Sakakibara, K. Sato, T. Kikuchi, S. Fukui, Y. Fukuchi-Mizutani, M. Nakao, M. Tanaka, Y. Kusumi, T. Nishino, T. (2000) Aureusidin synthase polyphaiol oxidase homolog responsible for flower coloration. Science, 290, 1163-6. 

UDP-Glc aureusidin 7-O-glucosyltransferase Isoflavonoids AU7GT 2.4.1.- UGT Patent app WOOO/4... 

Although it has long been thought, based on genetic mutant and biochemical evidence, that aurones are derived from chalcones, the biosynthetic mechanism has only recently been clarified, and some aspects of the enzymatic process still await in vivo proof An mRNA from A. majns, specifically expressed in the petal epidermal cells, has been shown to encode a recombinant protein with aureusidin synthase (AUS) activity.AUS is a variant polyphenol oxidase (PPO) that can catalyze conversion of either 2, 4, 6, 4-etrahydroxychalcone (naringenin chalcone) or 2, 4, 6, 3,4-pentahydroxychalcone to... 

Nakayama, T. et al., Aureusidin synthase a polyphenol oxidase homolog responsible for flower coloration. Science, 290, 1163, 2000. 

FIGURE 16.S Reactions catalyzed by the plant polyphenol oxidase, aureusidin synthase (AS), in the transformation of chalcones to aurones. (A) The biosynthesis of aureusidin from either tetra- or pentahydroxychalcone precursors through an ortho-diqmnone intermediate. (B) The aureusidin synthase-catalyzed formation of bracteatin from a pentahydroxychalcone precursor. 

Figure 3-7. Flavonoid biosynthesis (this page and next page). The enzymes involved in this pathway are (a) chalcone synthase (E.C. 2.3.1.73), (b) aureusidin synthase (E.C. 1.21.3.6), (c) chalcone isomerase (E.C. 5.5.1.6), (d) flavanone 3-hydroxylase (E.C. 1.14.11.9), (e) flavone synthase (E.C. 1.14.11.22), (f) flavonoid 3 -hydroxylase (E.C. 1.14.13.21),...

Nakayama T, Sato T, Fukui Y, Yonekura-Sakakibara K, Hayashi H, Tanaka Y, Kusumi T, Nishino T. 2001. Specificity analysis and mechanism of aurone synthesis catalyzed by aureusidin synthase, a polyphenol oxidase homolog responsible for flower coloration. FEBS Lett 499 107-111. 

Aurones (Phe C40(=0)=CH-Phe). Aurones (2-benzylidenebenzofuranones) derive from oxidation and cyclization of chalcone precursors to yield the corresponding benzofura-none (benzene fused with a five-membered furanone ring) Phenyl-CO- CH=CH—Phenyl + O2 — Benzofuranone = CH-Phenyl. Various aurones inhibit iodothyronine deiodinase, namely (numbering 1-9 in the bicyclic benzofuranone and 1 -6 in the benzylidene phenyl) aureusidin (4,6,3, 4 -tetrahydroxyaurone), bracteatin (4,6,3, 4, 5 - pentahydroxyaurone), maritimetin (6,7,3, 4 -tetrahydroxyaurone) and sulfuretin (6,3, 4 -trihydroxyaurone). 

The only other types of flavonoid substances which have to be considered are benzalcoumaranones (aurones, c/., Bate-Smith and Geissman, 1951), e.g., sulphuretin (XIII, R = H) and aureusidin (XIII, R = OB), chalcones, e.g., butein (XIV), and dihydrochalcones, e.g., phloretin (XV). The relationships between these types are admirably illustrated by Geissman and Hinreiner (1952). Table II is a somewhat modified... 

Aurones. Besides aureusidin (XXI, R == H), isolated from Antirrhinum majus, and leptosidin (XXIV), isolated from Coreopsis and Leptosyne... 

Kumar KS, Kumaresan R (2011) A quantum chemical study on the antioxidant properties of aureusidin and bracteatin. Int J Quant Chem 111 4483... 

Aureusidin synthase (AmASl), 1889 Aurones, 1621, 1887, 1889 Australian ewes, 2417 Autolyzate, 978-979 Autooxidation, 2370 Autopsy, 2409 Autumnaline, 461-476 Auxins, 192, 1830, 2774, 3198, 3591, 4044 Avenalumin I, 1569 Avena sativa, 1569 Avicermiaceae, 1552 Axinellamines, 268 Axinohydantoin, 268 Axonal membrane, 4065 Axone regeneration, 3219 Ayahuasca, 125, 1452 Ayurvedic, 1278, 3960 formulations, 3327, 3328 medications, 1399 medicinal system, 3476... 

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