The Decisive Step in Betaxanthin Biosynthesis Is a Spontaneous Reaction1

Experiments were performed to confirm that the aldimine bond formation is a spontaneous reaction, because attempts to find an enzyme catalyzing the last decisive step in betaxanthin biosynthesis, the aldimine formation, failed. Feeding different amino acids to betalain-forming hairy root cultures of yellow beet (Beta vulgaris L. subsp. vulgaris “Golden Beet”) showed that all amino acids (S- and R-forms) led to the corresponding betaxanthins. We observed neither an amino acid specificity nor a stereoselectivity in this process. In addition, increasing the endogenous phenylalanine (Phe) level by feeding the Phe ammonia-lyase inhibitor 2-aminoindan 2-phosphonic acid yielded the Phe-derived betaxanthin. Feeding amino acids or 2-aminoindan 2-phosphonic acid to hypocotyls of fodder beet (B. vulgaris L. subsp. vulgaris “Altamo”) plants led to the same results. Furthermore, feeding cyclo-3-(3,4-dihydroxyphenyl)-alanine (cyclo-Dopa) to these hypocotyls resulted in betanidin formation, indicating that the decisive step in betacyanin formation proceeds spontaneously. Finally, feeding betalamic acid to broad bean (Vicia faba L.) seedlings, which are known to accumulate high levels of Dopa but do not synthesize betaxanthins, resulted in the formation of dopaxanthin. These results indicate that the condensation of betalamic acid with amino acids (possibly including cyclo-Dopa or amines) in planta is a spontaneous, not an enzyme-catalyzed reaction.

Musica italiana in Francia : la riforma intitolata a Gluck /

Includes bibliographical references (p. 33-34).

Sechs Trios f[ür] 2 Violinen u[nd] Violoncell (B[asso] c[ontinuo]) (1746) /

Each volume has score and 3 parts.

Iphigenia in Aulis [ouverture]

Mode of access: Internet.

Iphigenia in Aulis, oper in drei akten

In portfolio.

Ouverture zur Oper Iphigenie in Aulis. Zwei Ausgaben:

Historical note by Altmann in German and English.

Alceste : opera en trois actes avec accompagnemente de pianoforte /

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Der Schilderungsstil in den homerischen Gleichnissen und den Denkmälern der kretisch-mykenischen und geometrischen Epoche.

Thesis--Strassburg.

Iphigenie in Aulis : Oper in 3 Akten /

Libretto by Du Roullet based on Racine's tragedy.

Jus et vis tripartito foedere juncta : in bello justo, in defensione privata, in executione judiciali adumbrata, seu Disputatio juridica, de vi justa, quam in alma Caesarea Regiaque Carolo-Ferdinandea Universitate Pragensi ...

Mode of access: Internet.

Xenophontis, sapientissimi & fortissimi viri, Quae extant opera : quorum interpretationem a diuersis editam Henricus Stephanus partim ipse recognouit, partim per alios recognoscendam curauit, in ijs potissimum locis in quibus minus tolerabilis esse videbatur. His praefixa est eiusdem Henrici Stephani oratio, De coniugendis cum Marte musis, exemplo Xenophontis . ...

ICCU,