Coenzyme Q

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UV SPECTRA	:	lmax 270 mm, E1%1cm = 455 in petroleum ether(Ref. 0037)
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To 1.0 g of 2,3-dimethoxy-5-methyl-hydroquinone in 5 ml of anhydrous dioxane is added at 18 - 20 1 ml of BF₃ etherate, and , over the course of 1 hour, 3.35 g of linalool in 10 ml of dioxane. The reaction mixture is stirred for 3 hours and then diluted with ether to a total volume of 150 ml. The ethereal solution is washed (2 x 50 ml) with a 5% solution of sodium bicarbonate and dried over anhydrous magnesium sulfate. The solvent is removed in vacuo, the remaining oil dissolved in 100 ml of anhydrous ether, and treated 18 hours with 5 g of freshly prepared silver oxide and 2 g of anhydrous magnesium sulfate. After filtering and evaporation, the residue is dissolved in 100 ml of petroleum ether (b.p. 40 - 60), washed with water (6 x 100 ml), and dried with anhydrous magnesium sulfate. The solvent is removed in vacuo, and the remaining product is subjected to preparative thin-layer chromatography on a layer of alumina deactivated with % water.
Solvent: hexane-ether (3 : 2). The elution of ubiquinone-2 from the alumina is accomplished with ether. Rf value : 0.56; 2,3-dimethoxy- 5-methyl-1,4-benzoquinone shows Rf 0.36. Yield: 16.8%. Ultraviolet absorption maximum at 272 m (E^1%_1cm = 400) (in hexane).(Ref. 0003) A new regio- and stereocontrolled synthesis of coenzyme Qn (n = 2,3,9,10) is described. Coupling of geranyltrimethyltin with 2,3-dimethoxy-5-methylbenzoquinone was successfully undertaken in the presence of BF₃^.OEt₂. After oxidation of the resulting mixture coenzyme Q₂ was obtained in 90% yield with more than 99% ₁₀ Delta² -trans stereochemistry. Similarly, all-trans coenzyme Q₉ and Q₁₀ were obtained in reasonable yields.(Ref. 0029)

Coenzyme Q functions as a lipid-soluble electron carrier in eukaryotes. In Saccharomyces cerevisiae, the enzymes responsible for the assembly of the polyisoprenoid side chain and subsequent transfer to para hydroxybenzoate (PHB) are encoded by the nuclear genes COQ₁ and COQ₂, respectively. Yeast mutants defective in coenzyme Q biosynthesis are respiratory defective and provide a useful tool to study this non-sterol branch of the isoprenoid biosynthetic pathway. A 5.5-kilobase genomic DNA fragment that was able to functionally complement a coq2 strain was isolated. Additional complementation analyses located the COQ₂ gene within a 2.1-kilobase HindIII-BglIII restriction fragment.
Sequence analyses revealed the presence of a 1,116-base pair open reading frame coding for a predicted protein of 372 amino acids and a molecular mass of 41,001 daltons. The amino acid sequence exhibits a typical amino-terminal mitochondrial leader sequence and six potential membrane spanning domains. Primer extension and Northern analyses indicate the gene is trascriptionally active. (Ref. 0022)

[0003]

AUTHOR	:	Obol'nikova, E. A., Volkova, O. I., and Samokhvalov, G. I.
TITLE	:	Synthetic studies of polyenes XXVIII. Complete synthesis of coenzyme Q2, Q3, Q4, and hexahydro-Q4
JOURNAL	:	Zhurnal Obshchei Khimii (English translation)
VOL	:	38 PAGE : 459 -462 (1966)

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[0022]

AUTHOR	:	Ashby, M. N., Kutsunai, S. Y., Ackerman, S., Tzagoloff, A., and Edwards, P. A.
TITLE	:	COQ2 is a candidate for the structural gene encoding para-hydroxybenzoate:polyprenyltransferase PubMed ID:1740455
JOURNAL	:	J Biol Chem.
VOL	:	267 PAGE : 4128-4136 (1992)

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[0029]

AUTHOR	:	Naruta, Y., and Maruyama, K.
TITLE	:	Regio- and stereocontrolled polyprenylation of quinones. A new synthetic method of coenzyme Q2, Q3, Q9, and Q10
JOURNAL	:	Chem. Letters
VOL	:	PAGE : 885 -888 (1979)

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[0037]

AUTHOR	:	Sommer,P., and Kofler,M.
TITLE	:	Physicochemical Properties and Methods of Analysis of Phylloquinones, Menaquinones, Ubiquinones, Plastoquinones, Menadione, and Related Compounds. PubMed ID:5340867
JOURNAL	:	Vitamins and Hormones
VOL	:	24 PAGE : 349 -399 (1966)

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