Biosynthetic Relationship between Ubichromenol and Ubiquinone

Joshi, V.C.; Jayaraman, J.; Ramasarma, T.

doi:10.1042/bj0920009c

Cited by 14 publications

(3 citation statements)

References 13 publications

(16 reference statements)

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“…Ob Chromenole-(6) der Coenzym-Q-Gruppe als Naturprodukte vorkommen, ist noch ungeklart. Die Isolierung der Chromenole unter genau kontrollierten Bedingungen dient als Argument fur ihr natiirliches Vorkommen7-10), jedoch fuhrten Untersuchungen mit radioaktiven Isotopen zu entgegengesetzten Ergebnissen [11][12][13]. Fur das naturliche Auftreten spricht, da13 das Chromenol des Coenzyms Q7, isoliert aus Torula-Hefe, anscheinend optisch aktiv ist 14).…”

Section: Ch30 Ch30unclassified

Coenzym Q, LIX Photochemische Cyclisierung von Coenzym Q zum D, L‐Chromenol

Moore

Folkers

1965

Justus Liebigs Ann. Chem.

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Bd. 684 2-Amino-4-hydroxymethyl-pyrimidin (111). -900 mg (6 mMol) ZI werden in die Extraktionshiilse einer Soxhletapparatur gefiillt. Der Kolben enthalt 420 mg (10 mMol) LiAlH4 in 100 ccm absol. Ather. Nach 10 Stdn. war die Reaktion beendet. AnschlieRend wurde auf --20" gekiihlt und rnit 20ccm k h a n o l zersetzt. Aus der zur Trockne eingedampften Losung wurde I11 rnit Ather in einer Soxhletapparatur extrahiert. Ausbeute 75 mg (9.4%); Schmp. 145".CsH7N30 (

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Section: Ch30 Ch30unclassified

Coenzym Q, LIX Photochemische Cyclisierung von Coenzym Q zum D, L‐Chromenol

Moore

Folkers

1965

Justus Liebigs Ann. Chem.

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“…Therefore, it would be of interest whether chromanol analogues of UQ, such as ubichromanol (UCa) and ubichromenol (UCe), are natively present in mammalian cells and whether, in principle, chromanol analogues of UQ oxidize to UQ-like products. In the past, there have been only a few reports on the presence of UCe in liver homogenates (17)(18)(19). Links questioned some of these reports by proving that chromatographic materials, such as aluminum oxide (20), can transform UQ to UCe.…”

Section: Introductionmentioning

confidence: 99%

A New Ubiquinone Metabolite and Its Activity at the Mitochondrial bc₁ Complex

Gille

Stamberg

Jäger

et al. 2007

Chem. Res. Toxicol.

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Ubichromanol, a reductive cyclization product of ubiquinone, acts as radical scavenging antioxidant and is similarly effective as alpha-tocopherol. However, nothing is known so far on the two-electron oxidation product of this antioxidant and its bioactivity. This study demonstrates that ubichromanol yields a ubiquinone-like compound with a hydroxyl-substituted side chain (UQOH) on oxidation. HPLC/MS and HPLC/ECD measurements revealed its natural presence in bovine liver mitochondria. The bioactivity of this formerly unknown compound as substrate for mitochondrial complex III was tested by measurements of the quinol:cytochrome c oxidoreductase activity in bovine submitochondrial particles and isolated mitochondrial bc1 complex. Consistently in both model systems, reduced UQOH exhibited substrate efficiencies below that of native ubiquinone but a significantly higher efficiency than alpha-tocopheryl quinone. Model calculations revealed that on binding of reduced UQOH to the bc1 complex the polar hydroxyl group was located close to hydrophobic amino acid residues. This fact could in part explain the lower efficiency of reduced UQOH in comparison to ubiquinone as a substrate for the mitochondrial bc1 complex. Therefore, the hydroxylation of the aliphatic or isoprenoid side chains of bioquinones, which is typical for quinoid oxidation products of chromanols, such as alpha-tocopherol and ubichromanol, disturbs substrate binding at the mitochondrial electron-transfer complexes, which usually interact with ubiquinone.

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“…The recoveries of radioactivity in these fractions were usually about 80% of the total unsaponifiable lipids. Determinations of ubiquinone, 'sterols' and radioactivity in the samples were made as described by Joshi, Jayaraman & Ramasarma (1963a).…”

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confidence: 99%

Metabolism of ubiquinone in relation to thyroxine status

Inamdar

Ramasarma

1969

Biochemical Journal

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1. Under conditions of thyrotoxicosis induced by feeding rats with iodinated casein, ubiquinone concentration was found to increase in the liver by increased synthesis and by partly decreased catabolism leading to its accumulation. The increased ubiquinone was found primarily in the mitochondrial and supernatant fractions. 2. Supplementing the diet with thyroxine, at less than toxic doses, also increased the synthesis and the concentration of ubiquinone in the liver. 3. In the condition of hypothyroidism obtained by feeding rats with thiouracil the concentration and the synthesis of ubiquinone in the liver showed a small decrease. 4. Synthesis of ubiquinone in liver slices was partially inhibited by addition of thyroxine in vitro. Therefore the activation effect on ubiquinone synthesis of excess of thyroxine in the intact animals appears to be by an indirect mechanism.

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Biosynthetic Relationship between Ubichromenol and Ubiquinone

Cited by 14 publications

References 13 publications

Coenzym Q, LIX Photochemische Cyclisierung von Coenzym Q zum D, L‐Chromenol

Coenzym Q, LIX Photochemische Cyclisierung von Coenzym Q zum D, L‐Chromenol

A New Ubiquinone Metabolite and Its Activity at the Mitochondrial bc₁ Complex

Metabolism of ubiquinone in relation to thyroxine status

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Biosynthetic Relationship between Ubichromenol and Ubiquinone

Cited by 14 publications

References 13 publications

Coenzym Q, LIX Photochemische Cyclisierung von Coenzym Q zum D, L‐Chromenol

Coenzym Q, LIX Photochemische Cyclisierung von Coenzym Q zum D, L‐Chromenol

A New Ubiquinone Metabolite and Its Activity at the Mitochondrial bc1 Complex

Metabolism of ubiquinone in relation to thyroxine status

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Product

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A New Ubiquinone Metabolite and Its Activity at the Mitochondrial bc₁ Complex