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2776411 
Journal Article 
Observations on the Biosynthesis of Ubiquinones by Animals 
Whistance, GR; Field, FE; Threlfall, DR 
1971 
Yes 
European Journal of Biochemistry
ISSN: 0014-2956
EISSN: 1432-1033 
NIOSH/00133297 
18 
1 
46-52 
The biosynthesis of ubiquinones from p-hydroxybenzoic-acid (99967) was investigated in the higher animals. Lipids were extracted from the hearts of grey squirrels, guinea-pigs, hares, oxen, pheasants, pig, sheep, widgeon, woodcock, and mouse liver. Extraction was done by saponification and by solvent extraction. Carbon-14 labeled benzoic-acid and p-hydroxybenzoic-acid were given by intraperitoneal injection to male Wistar-rats. Rat liver slices were incubated for four hours at 37 degrees-C in a solution containing labeled C-14-p-hydroxybenzoic-acid. Isoprenoid phenols and quinones were detected and isolated by adsorptive and reversed phased thin layer chromatography. Tissues were examined for 2-polyprenylphenol, 4-benzoquinone, and 5-demethoxyubiquinone. The rate of radioactivity incorporation was maximal over a period from 0 to 4 hours, after which it declined to 0 and became negative. After 16 hours, 70 percent of the radioactivity was recovered from urine and 6 percent from feces. No incorporation of benzoic-acid into ubiquinones occurred in rats. The authors conclude that the finding of at least two ubiquinones in the animal tissues reflects a lack of absolute specificity on the part of the enzymes involved in ubiquinone synthesis in regard to the length of the isoprenoid side chain.