Eckhard Leistner

Biosynthesis of morindone and alizarin in intact plants and cell suspension cultures of Morinda citrifolia

Chrysophanol (1,8-dihydroxy-3-methylanthraquinone) is an acetate-derived anthraquinone which is substituted in both benzenoid rings. Morindone (1,5,6-trihydroxy-2-methylanthraquinone) is also substituted in both rings but is shown to be derived from shikimic acid via o-succinoylbenzoic acid.

Aglycones and glycosides of oxygenated naphthalenes and a glycosyltransferase from Juglans

Abstract 4-Hydroxy-1-naphthalenyl-β- D -glucopyranoside, a new natural product, as well as 1,4-naphthoquinone, juglone, and 4,8-dihydroxy-1-naphthalenyl-β

Mode of incorporation of precursors into alizarin (1,2-dihydroxy-9,10-anthraquinone)☆

Abstract The biosynthesis of alizarin (1,2-dihydroxy-9,10-anthraquinone) in Rubia tinctorum L. has been studied by tracer techniques. Specific incorporation of label from carboxyl- 14 C- d -shikimic acid, 2- 14 C- dl -glutamic acid and 5- 14 C- dl -Mevalonic acid suggests that these compounds provide the carbon skeleton of alizarin. Nonsymmetrical incorporation of label from carboxyl- 14 C- d -shikimic acid and 2- 14 C- dl -glutamic acid into alizarin indicates that the symmetrical 1,4-naphthoquinone is probably not an intermediate. Activity from o -(succinyl-2,3 14 C)-benzoic acid was found in the substituted benzene ring of alizarin. These data indicate that α-ketoglutaric acid or a derivative thereof combines with shikimic acid, chorismic acid or phrephenic acid to give o -succinylbenzoic acid which is then transformed to a nonsymmetrical intermediate γ,γ-Dimethylallylpyrophosphate is then attached, ring closure and further modification leading to alizarin.

1,4-Naphthoquinone, an intermediate in juglone (5-hydroxy-1,4-naphthoquinone) biosynthesis.

Abstract Evidence is presented which shows that 1,4-naphthoquinone, a new natural product, is involved in the biosynthesis ofjuglone in Juglans regia .

A second pathway leading to anthraquinones in higher plants

Abstract The biosynthesis of chrysophanol (1,8-dihydroxy-3-methylanthraquinone) and emodin (1,6,8-trihydroxy-3-methylanthraquinone) has been studied in Rhamnus frangula and Rumex alpinus . Degradation of both anthraquinones after feeding 1- 14 C-acetate and 2- 14 C-acetate showed that these compounds are derived from acetate by linear combination. 14 C-Shikimate and 14 C-mevalonate were not incorporated.

Stereochemistry of reactions catalysed by l-lysine decarboxylase and diamine oxidase

Abstract The decarboxylation of l -lysine to yield cadaverine, catalysed by l -lysine decarboxylase (EC 4.1.1.18) takes place with retention of configuration. In the course of the dehydrogenation of cadaverine by diamine oxidase (EC 1.4.3.6) from pea seedlings, the pro- S -hydrogen is labilized.

Metabolic relation between naphthalene derivatives in Juglans

Abstract It has been shown by labelling experiments that 4-oxo-α-tetralone and β-hydrojuglone may be involved in the biosynthesis of naphthoquinols in Juglans regia . Experiments on the metabolic role of aglycones and glucosides are discussed and a hypothetical scheme for these biosynthetic relationships is presented.

O-succinylbenzoate: Coenzyme a ligase from anthraquinone producing cell suspension cultures of Galium mollugo

Abstract The o -succinylbenzoate: coenzyme A ligase, an enzyme involved in anthraquinone biosynthesis, has been purified from an extract of a Galium mollugo plant cell suspension culture. The properties of the enzyme such as kinetic data, temperature and pH optimum, stability, specificity and molecular weight were determined. The data were compared to those obtained from the o -succinylbenzoate: coenzyme A ligase from Mycobacterium phlei , an enzyme involved in menaquinone biosynthesis. It was shown that the plant and bacterial enzymes are completely different with respect to specificity, molecular weight and mechanism of activation.

A study of the bacterial community in the root system of the maytansine containing plant Putterlickia verrucosa

Maytansinoid compounds are ansa antibiotics occurring in the bacterium Actinosynnema pretiosum, in mosses and in higher plants such as Putterlickia verrucosa (E. Meyer ex Sonder) Szyszyl. The disjunct occurrence of maytansinoids has led to the consideration that plant-associated bacteria may be responsible for the presence of maytansinoids in P. verrucosa plants. Investigation of the bacterial community of this plant by molecular methods led to the observation that A. pretiosum, a maytansine-producing bacterium, is likely to be an inhabitant of the rhizosphere and the endorhiza of P. verrucosa.

Enzyme activities in extracts of anthraquinone-containing cells of Galium mollugo

Abstract Cell suspension cultures of Galium mollugo produce large amounts of anthraquinones which interfere with measurements of some enzyme activities. A method has been developed for determining enzyme activities in protein extracts of these cells using protamine sulfate and Servachrome XAD2. The efficiency of this method was demonstrated by measuring the activity of an enzyme sensitive to anthraquinones, viz. chorismate mutase (EC 5.4.99.5).