Notizen: On the mode of incorporation of shikimic acid into 2-hydroxy-1,4-naphthoquinone (lawsone)

Biosynthesis of vitamin K (menaquinone) in bacteria.

“…The first test of the hypothesis used a system for which the chemical degradations were simpler than those for menaquinones. Various plants produce lawsone (2hydroxy-1,4-naphthoquinone), and it was known that shikimate utilization was involved (236); furthermore, in juglone (5-hydroxy-1,4naphthoquinone) biosynthesis in Juglans regia, C-2 or C-3 (or both) of ring B were formed from the methylene carbon of malonate or the methyl carbon of acetate (136; compare the bacterial results just described). Campbell, therefore, administered [ shoots of Impatiens balsamina plants, assuming they would be converted, respectively, to pyruvate, oxaloacetate, and 2-ketoglutarate (40).…”

Pathways of biosynthesis of aromatic amino acids and vitamins and their control in microorganisms.

“…It was later shown that the shikimate was incorporated into the benzene ring of the naphthoquinone (29). More recently, evidence has been obtained that the carboxyl group of shikimate is incorporated into vitamin K (19) and also into a plant naphthoquinone (177).…”

Biosynthèse du noyau naphtoquinonique des ménaquinones bactériennes

“…Ce melange est port6 B Bbullition pendant 1 h 30 min et le gaz carbonique d6gag6, entrain6 par un courant d'azote, est recueilli dans 4 ml de soude 2 N d6carbonat6e. Celle-ci est ensuite trait6e par 5 [9] avaient trouv6 une incorporation sp6cifique de l'acide p-hydroxybenzoYque dans la lawsone de I m p t i e m balsamina; ce resultat a ensuite BtB contest6 par Zenk et Leistner [7]. L'aldehyde p-hydroxybenzoique a dt6 identifie comme un presurseur direct des ubiquinones chez R. rubrum [25] SchBma.…”

“…Cependant, lea premiers resultats obtenus dans ce domaine ont montre que l'acide D-shikimique constituait le precurseur direct de la partie aromatique du noyau naphtoquinonique, aussi bien pour les m6naquinones bacteriennes [3-61 que pour plusieurs naphtoquinones sans chaine laterale isol6es des veg6taux [7 -91. Differents composes aromatiques ont 6te depuis impliques comme intermediaires possibles entre l'acide shikimique et la 1,4-naphtoquinone : divers acides aromatiques [lo], l'acide 3,4-dihydroxybenzoique [4,6], l'acide p-hydroxybenzoique [ll] et l'n-naphtol [7]. La preparation de ces composes marques et les tentatives d'incorporation effectuees chez les plantes ou les batteries ont conduit A Bliminer certains d'entre eux ; pour d'autres, les resultats demeurent contradictoires [5,12].…”