Biosynthesis of polyprenols in higher plants. The elimination of the pro-4S hydrogen atom of mevalonic acid during the formation of their (Z)-isoprene chain

1983 ◽  
Vol 105 (19) ◽  
pp. 6178-6179 ◽  
Author(s):  
Takayuki Suga ◽  
Toshifumi Hirata ◽  
Tadashi Aoki ◽  
Tsuyoshi Shishibori
Keyword(s):  
Hydrogen Atom ◽  
Higher Plants ◽  
Mevalonic Acid

scholarly journals Biosynthesis of geraniol and nerol and their β-d-glucosides in Perlargonium graveolens and Rosa dilecta

1972 ◽  
Vol 130 (4) ◽  
pp. 1045-1054 ◽  
Author(s):  
Derek V. Banthorpe ◽  
Geoffrey N. J. Le Patourel ◽  
Martin J. O. Francis
Keyword(s):  
Double Bond ◽  
Hydrogen Atom ◽  
Higher Plants ◽  
Animal Tissue ◽  
Labelling Pattern ◽  
Isopentenyl Pyrophosphate ◽  
Pelargonium Graveolens ◽  
Dimethylallyl Pyrophosphate

1. 3R-[2-14C]Mevalonate was incorporated into geranyl and neryl β-d-glucosides in petals of Rosa dilecta in up to 10.6% yield, and the terpenoid part was specifically and equivalently labelled in the moieties derived from isopentenyl pyrophosphate and 3,3-dimethylallyl pyrophosphate. A similar labelling pattern, with incorporations of 0.06–0.1% was found for geraniol or nerol formed in leaves of Pelargonium graveolens The former results provide the best available evidence for the mevalonoid route to regular monoterpenes in higher plants. 2. Incorporation studies with 3RS-[2-14C,(4R)-4-3H1]-mevalonate and its (4S)-isomer showed that the pro-4R hydrogen atom of the precursor was retained and the pro-4S hydrogen atom was eliminated in both alcohols and both glucosides. These results suggest that the correlation of retention of the pro-4S hydrogen atom of mevalonate with formation of a cis-substituted double bond, such as has been found in certain higher terpenoids, does not apply to the biosynthesis of monoterpenes. It is proposed that either nerol is derived from isomerization of geraniol or the two alcohols are directly formed by different prenyltransferases. Possible mechanisms for these processes are discussed. 3. The experiments with [14C,3H]mevalonate also show that in these higher plants, as has been previously found in animal tissue and yeast, the pro-4S hydrogen atom of mevalonate was lost in the conversion of isopentenyl pyrophosphate into 3,3-dimethylallyl pyrophosphate.

scholarly journals Isoprenoid biosynthesis in higher plants and in Escherichia coli: on the branching in the methylerythritol phosphate pathway and the independent biosynthesis of isopentenyl diphosphate and dimethylallyl diphosphate

2002 ◽  
Vol 366 (2) ◽  
pp. 573-583 ◽  
Author(s):  
Jean-François HOEFFLER ◽  
Andréa HEMMERLIN ◽  
Catherine GROSDEMANGE-BILLIARD ◽  
Thomas J. BACH ◽  
Michel ROHMER
Keyword(s):  
Escherichia Coli ◽  
Higher Plants ◽  
Mevalonic Acid ◽  
Cell Suspension Cultures ◽  
Mep Pathway ◽  
Isopentenyl Diphosphate ◽  
Higher Plant ◽  
Methylerythritol Phosphate Pathway ◽  
Dimethylallyl Diphosphate ◽  
Deuterium Retention

In the bacterium Escherichia coli, the mevalonic-acid (MVA)-independent 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway is characterized by two branches leading separately to isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). The signature of this branching is the retention of deuterium in DMAPP and the deuterium loss in IPP after incorporation of 1-[4-2H]deoxy-d-xylulose ([4-2H]DX). Feeding tobacco BY-2 cell-suspension cultures with [4-2H]DX resulted in deuterium retention in the isoprene units derived from DMAPP, as well as from IPP in the plastidial isoprenoids, phytoene and plastoquinone, synthesized via the MEP pathway. This labelling pattern represents direct evidence for the presence of the DMAPP branch of the MEP pathway in a higher plant, and shows that IPP can be synthesized from DMAPP in plant plastids, most probably via a plastidial IPP isomerase.

scholarly journals Incorporation of [2−14C,(5R)-5−3H1]mevalonic acid into cholesterol by a rat liver homogenate and into β-sitosterol and 28-isofucosterol by Larix decidua leaves

1969 ◽  
Vol 114 (4) ◽  
pp. 885-892 ◽  
Author(s):  
L J Goad ◽  
G. F. Gibbons ◽  
Loretta M. Bolger ◽  
H H Rees ◽  
T W Goodwin
Keyword(s):  
Double Bond ◽  
Hydrogen Atom ◽  
Rat Liver ◽  
Cholesterol Biosynthesis ◽  
Liver Homogenate ◽  
Mevalonic Acid ◽  
Atomic Ratio ◽  
Larix Decidua ◽  
Tritium Atom

1. Incubation of a rat liver homogenate with 3R-[2−14C,(5R)-5−3H1]mevalonic acid gave cholesterol with 3H/14C atomic ratio 6:5. 2. Conversion of the labelled cholesterol into 3β-acetoxy-6-nitrocholest-5-ene or cholest-4-ene-3,6-dione resulted in the loss of one tritium atom from C-6. 3. These results show that during cholesterol biosynthesis the 6α-hydrogen atom of a precursor sterol is eliminated during formation of the C-5–C-6 double bond. 4. Incorporation of 3R-[2−14C,(5R)-5−3H1]mevalonic acid into the sterols of larch (Larix decidua) leaves gave labelled cycloartenol and β-sitosterol with 3H/14C atomic ratios 6:6 and 6:5 respectively. 5. One tritium atom was lost from C-6 on conversion of the labelled β-sitosterol into either 3β-acetoxy-6-nitrostigmast-5-ene or stigmast-4-ene-3,6-dione, demonstrating that formation of the C-5–C-6 double bond of phytosterols also involves the elimination of the 6α-hydrogen atom of a precursor sterol. 6. The 3R-[2−14C,(5R)-5−3H1]mevalonic acid was also incorporated by larch (L. decidua) leaves into a sterol that co-chromatographed with 28-isofucosterol. Confirmation that the radioactivity was associated with 28-isofucosterol was obtained by co-crystallization with carrier 28-isofucosterol and ozonolysis of the acetate to give radioactively labelled 24-oxocholesteryl acetate. 7. The significance of these results to phytosterol biosynthesis is discussed.

STEREOCHEMISTRY OF THE C-4 PROCHIRAL HYDROGEN ATOM ELIMINATION OF MEVALONATE IN THE BIOSYNTHESIS OF POLYPRENOLS IN HIGHER PLANTS

1983 ◽  
Vol 12 (9) ◽  
pp. 1467-1470 ◽  
Author(s):  
Takayuki Suga ◽  
Tadeshi Aoki ◽  
Toshifumi Hirata ◽  
Yoshio Saragai
Keyword(s):  
Hydrogen Atom ◽  
Higher Plants

scholarly journals Studies in phytosterol biosynthesis. Mechanism of biosynthesis of cycloartenol

1968 ◽  
Vol 107 (3) ◽  
pp. 417-426 ◽  
Author(s):  
H H Rees ◽  
L J Goad ◽  
T W Goodwin
Keyword(s):  
Solanum Tuberosum ◽  
Hydrogen Atom ◽  
Mevalonic Acid ◽  
Atomic Ratio ◽  
Side Chain ◽  
Hydrogen Migration ◽  
Biosynthetic Precursor

1. The mechanism of cycloartenol biosynthesis in leaves of Solanum tuberosum was investigated with the use of [2−14C,(4R)-4−3H1]mevalonic acid. 2. The 3H/14C atomic ratio in cycloartenol was 6:6, the same as that in squalene; this eliminates lanosterol as a possible biosynthetic precursor of cycloartenol, and indicates that a hydrogen migration from C-9 to C-8 occurs. 3. Chemical isomerization of the cycloartenol to lanosterol (3H/14C ratio 5:6) and parkeol (3H/14C ratio 6:6) confirms the hydrogen migration from C-9 to C-8. 4. Possible mechanisms for the biosynthesis of cycloartenol and parkeol are discussed. 5. The 3H/14C ratio for 24-methylenecycloartanol was 6:6, demonstrating that the hydrogen atom at C-24 is retained during alkylation of the cycloartenol side chain.

scholarly journals The role of a cholesta-8,14-dien-3β-ol system in cholesterol biosynthesis

1969 ◽  
Vol 111 (5) ◽  
pp. 757-761 ◽  
Author(s):  
M. Akhtar ◽  
I. A. Watkinson ◽  
A. D. Rahimtula ◽  
D. C. Wilton ◽  
K. A. Munday
Keyword(s):  
Hydrogen Atom ◽  
Cholesterol Biosynthesis ◽  
Tritiated Water ◽  
Mevalonic Acid ◽  
Hydrogen Atoms ◽  
Steroid Biosynthesis ◽  
Methyl Group

The biosynthesis of cholesterol from squalene and tritiated water is described. Degradation of the cholesterol indicated that C-15 may be involved in cholesterol biosynthesis. In accordance with this view it is shown that in the conversion of [2RS−3H2]mevalonic acid into cholesterol one of the hydrogen atoms at C-15 is removed. A mechanism for the removal of the 14α-methyl group in steroid biosynthesis that involves the labilization of a C-15 hydrogen atom is outlined. In accordance with the requirement of this scheme it is shown that 4,4′-dimethyl-cholesta-8,14-dien-3β-ol is converted into cholesterol.

scholarly journals Retention of the 4-pro-R hydrogen atom of mevalonate at C-2,2′ of bacterioruberin in Halobacterium halobium

1980 ◽  
Vol 187 (1) ◽  
pp. 261-264 ◽  
Author(s):  
I E Swift ◽  
B V Milborrow
Keyword(s):  
Hydrogen Atom ◽  
Mevalonic Acid ◽  
Halobacterium Halobium ◽  
Intact Cells

Intact cells of Halobacterium halobium fed with (3R,4R)-[2-14C,4-3H1]mevalonic acid were found to incorporate label into acyclic C40 and C50 carotenoids, of which bacterioruberin was the most abundant. The 14C/3H ratios of the isolated carotenoids demonstrated that the 4-pro-R hydrogen atom of mevalonic acid was retained at the C-2 and C-2′ positions of bacterioruberin. Diphenylamine was found to inhibit the production of bacterioruberin.

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