Evidence of alkane synthesis by the sciatic nerve of the rabbit

Cassagne, Claude; Darriet, D.; Bourre, Jean‐Marie

doi:10.1016/0014-5793(77)80883-1

Cited by 33 publications

(8 citation statements)

References 15 publications

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“…Indeed, the distribution of alkanes within CIE epidermal strata and the reciprocal decrease in the fatty acid/triglyceride fraction raises the possibility that these hydrocarbons are locally generated. Recent work that demonstrates alkane biosynthesis in mouse sciatic nerve cell-free preparations lends further support to this possibility ( 14). Regardless of their source, there is reason to believe that n-alkanes may play an important role in disease pathogenesis.…”

Section: Discussionmentioning

confidence: 93%

Elevated n-alkanes in congenital ichthyosiform erythroderma. Phenotypic differentiation of two types of autosomal recessive ichthyosis.

Williams¹,

Elias²

1984

J. Clin. Invest.

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Abstract. Previously considered to represent a single genetic disorder, autosomal recessive ichthyosis was examined in clinical and lipid biochemical studies of 18 patients with this condition and instead disclosed to be two distinct diseases. Six patients displayed clinical features of classical lamellar ichthyosis (LI), which is characterized by monomorphous features, including large, dark, platelike scales, severe ectropion, and a uniformly severe, unremitting course. 11 patients displayed clinical features of nonbullous congenital ichthyosiform erythroderma (CIE) characterized by fine white scales, prominent erythroderma, a milder course, and a variable prognosis. CIE could be separated biochemically from LI by the invariable presence ofelevated quantities of n-alkanes in scale (CIE, 24.8±1.9% vs. LI, 7.2+1.6%, and normal, 6.5±0.9%), which suggested a primary disorder in neutral lipid metabolism. In light ofthe distinctive clinical features of each, these biochemical studies indicate that autosomal recessive ichthyosis comprises two distinct disorders.

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Section: Discussionmentioning

confidence: 93%

Elevated n-alkanes in congenital ichthyosiform erythroderma. Phenotypic differentiation of two types of autosomal recessive ichthyosis.

Williams¹,

Elias²

1984

J. Clin. Invest.

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“…The main component of the sex pheromone produced by the female housefly is (Z)-9-tricosene (Z9-23:Hy) (3), which functions as a short-range attractant and stimulant (4). In vertebrates, hydrocarbons function in the myelin sheath of peripheral nerves (5) and as components of uropygial gland secretions (6).…”

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confidence: 99%

Unusual mechanism of hydrocarbon formation in the housefly: cytochrome P450 converts aldehyde to the sex pheromone component (Z)-9-tricosene and CO2.

Reed

Vanderwel

Choi

et al. 1994

Proc. Natl. Acad. Sci. U.S.A.

116

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An unusual mechanism for hydrocarbon biosynthesis is proposed from work examining the formation of (Z)-9-tricosene (Z9-23:Hy), the major sex pheromone component of the female housefly, Musca domestica. Incubation of (Z)-15-[1-'4C1-and (Z)-15- [15,16-3H2jtetracosenoic These data demonstrate an unusual mechanism for hydrocarbon formation in insects in which the acyl-CoA is reduced to the corresponding aldehyde and then carbon-1 is removed as CO2. The requirement for NADPH and 02 and the inhibition by CO and the antibody to cytochrome P450 reductase strongly implicate the participation of a cytochrome P450 in this reaction.Long-chain hydrocarbons are abundant components in the cuticular lipids of plants and insects (1, 2), where they function to prevent water loss from the surface of the organism. In some insect species, including the housefly, Musca domestica, hydrocarbon components function as sex pheromones. The main component of the sex pheromone produced by the female housefly is (Z)-9-tricosene (Z9-23:Hy) (3), which functions as a short-range attractant and stimulant (4). In vertebrates, hydrocarbons function in the myelin sheath of peripheral nerves (5) and as components of uropygial gland secretions (6).The mechanism for hydrocarbon biosynthesis has proven to be elusive. Studies in the 1920s (7) suggested that two fatty acids condense head-to-head to form a ketone that is then reduced to the alkane. In an elegant series of experiments in the 1960s (reviewed in ref. -8), Kolattukudy and coworkers demonstrated that hydrocarbons are formed by the elongation of fatty acids, which are then converted to hydrocarbon by the loss of the carboxyl group, which was presumed to be a decarboxylation reaction (9,10). More recently, Kolattukudy and coworkers have obtained evidence from studies in a microorganism (11,12), a plant (13), a vertebrate (6), and an insect (14) that long-chain fatty acyl groups are reduced to aldehydes and then converted to hydrocarbons by a reductive decarbonylation mechanism. This mechanism does not require reduced pyridine nucleotides, and the carbonyl carbon is released as CO. In contrast, Gorgen and coworkers (15,16) presented evidence that 1-alkenes are formed by a decarboxylation mechanism in both plants and insects. We present evidence in this paper that hydrocarbon formation in the housefly occurs by the reduction of a long-chain acyl-CoA to an aldehyde that is then converted to the hydrocarbon and CO2 by a reaction that requires NADPH and 02 and involves cytochrome P450.

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“…Widespread occurrence of hydrocarbons in animals, accumulation of hydrocarbons under pathological conditions (3,4), demonstrated biosynthesis of hydrocarbons in mammalian nerve tissue (2), and decreased hydrocarbon synthesis associated with neurological disorders (5,6) suggest important biological functions for this class of simple compounds.…”

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confidence: 99%

A cobalt-porphyrin enzyme converts a fatty aldehyde to a hydrocarbon and CO.

Dennis

Kolattukudy

1992

Proc. Natl. Acad. Sci. U.S.A.

179

120

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The final step in hydrocarbon biosynthesis involves loss of CO from a fatty aldehyde. This decarbonylation is catalyzed by microsomes from Botyrococcus braunu. Among the several detergents tested for solubiliing the decarbonylase, octyl fi-glucoside (0.1%) was found to be the most effective and released 65% ofthe enzyme activity in soluble form. FPLC ofthe solubilized enzyme preparation with Superose 6 followed by ion-exchange FPLC with Mono Q resulted in 200-fold increase in specific activity with 7% recovery. The purified enzyme released nearly 1 mol of CO for each mol of hydrocarbon.SDS/PAGE of the enzyme preparation showed two protein bands of equal intensity at 66 and 55 kDa. The absorption spectrum of the enzyme with bands at 410 un, 425 um, 580 mn, and 620 un suggests the presence of a porphyrin. Electron microprobe analysis revealed that the enzyme contained Co. Purification of the decarbonylase from B. braunii grown in "CoC12 showed that 57Co coeluted with the decarbonylase.These results suggest that the enzyme contains Co that might be part of a Co-porphyrin, although a corrin structure cannot be ruled out. Co-protoporphyrin IX itself caused decarbonylation ofoctadecanal at 60'C, whereas the metal ion or protoporphyrin alone, or several other metal porphyrins, did not cause decarbonylation. These results strongly suggest that biosynthesis of hydrocarbons is effected by a microsomal Co-porphyrincontaining enzyme that catalyzes decarbonylation of aldehydes and, thus, reveal a biological function for Co in plants.Aliphatic nonisoprenoid hydrocarbons are ubiquitous in living organisms in both the plant and animal kingdoms (1, 2). Widespread occurrence of hydrocarbons in animals, accumulation of hydrocarbons under pathological conditions (3,4), demonstrated biosynthesis of hydrocarbons in mammalian nerve tissue (2), and decreased hydrocarbon synthesis associated with neurological disorders (5, 6) suggest important biological functions for this class of simple compounds.On the basis of the results obtained with specifically labeled precursors in higher plant tissues, it was proposed that n-hydrocarbons are produced by elongation of a fatty acid followed by the loss of the carboxyl carbon (7-9). Subsequent studies with insects (10) and mammals (2) supported this mechanism for alkane biosynthesis. Microsomal preparations from plant and animal tissues that generate alkanes have been shown to catalyze elongation offatty acids (11,12). The nature of the reaction that results in the loss of the carboxyl carbon remained obscure as the chemical nature of the immediate precursors of hydrocarbon was unknown until recently. Aldehydes with one carbon more than the alkanes were found to accumulate when hydrocarbon synthesis was inhibited by thiol compounds such as dithioerythritol (DTE) (13). In cell-free preparations that generate hydrocarbons, the observation that an aldehyde with one carbon more than the hydrocarbon was formed suggests that the aldehyde might be the immediate precursor of hydrocarbons (14). Ho...

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Evidence of alkane synthesis by the sciatic nerve of the rabbit

Cited by 33 publications

References 15 publications

Elevated n-alkanes in congenital ichthyosiform erythroderma. Phenotypic differentiation of two types of autosomal recessive ichthyosis.

Elevated n-alkanes in congenital ichthyosiform erythroderma. Phenotypic differentiation of two types of autosomal recessive ichthyosis.

Unusual mechanism of hydrocarbon formation in the housefly: cytochrome P450 converts aldehyde to the sex pheromone component (Z)-9-tricosene and CO2.

A cobalt-porphyrin enzyme converts a fatty aldehyde to a hydrocarbon and CO.

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