Biogenese der Betalaine Biotransformation von Dopa und Tyrosin in den Betalaminsäureteil des Betanins. Vorläufige Mitteilung
✍ Scribed by H. E. Miller; H. Rösler; A. Wohlpart; H. Wyler; M. E. Wilcox; H. Frohofer; T. J. Mabry; André S. Dreiding
- Publisher
- John Wiley and Sons
- Year
- 1968
- Tongue
- German
- Weight
- 291 KB
- Volume
- 51
- Category
- Article
- ISSN
- 0018-019X
No coin nor oath required. For personal study only.
✦ Synopsis
During studics on the biogenesis of betalains (I) in cactus fruits (Opuntia sp.). DLdopa-l-[14C] and -Z-[14C] were incorporated into betanin (111) which was obtained radiopure after crystallization. The specific activity remained constant after conversion to betanitlin (IV) and to a neobctanidin derivative (IX) . Reaction of radiobetanin with proline afforded indicaxanthin (V) carrying more than 90% of the radioactivity. Dopa (VI) is thus an efficient precursor for betalamic acid (VIII) but not for cyclodopa (VII) . Decarboxylation of radiobetanidin and radioindicaxanthin showed that the carboxyl group of dopa remained a carboxyl group in the biotransformation to betalaniic acid. It is concludcd that the aromatic ring of dopa is cleavcd and that re-cyclization involving the nitrogen generates the dihydropyridine moiety. Under the same conditions mcvalonic acid, aspartic acid and phenplalanine showed low incorporations. Studies with beet seedlings and ~~-d o p a -l -[ ~~C ] ,
-2-[14C] and ~i ~-t y r o s i n c -l -[ ~~C ] afforded similar results but with low incorporations.
1) Eine ausfdhrliche Mitteilung ist in Vorbercitung.
- Xational Institutes of Health Postdoctoral Fellow 1967/68.