Tetramethylhexadecanoic acid

Authentic standards of both series were prepared using combinations of the techniques outlined earlier. Members of series 1 were obtained by acylation of the necessary 2-alkylthiophene with 3,7,11,15-tetramethylhexadecanoic acid and reduction of the resulting ketone (Figure 25). 

Problem 33.2 (a) Acetate is not the only building block for the long chains of lipids. From a 50 million-year-old shale (see Problem 33.1)—as well as from modem organisms—there has been isolated 3,7,11,15-tetramethylhexadecanoic acid. 

Phytanic acid (3,7,11,15-tetramethylhexadecanoic acid), a component of the human diet that is derived from phytol, a constituent of chlorophyll, is not degraded by p-oxidation because its 3-methyl group interferes with this process. Instead, phytanic acid is chain-shortened by a-oxidation in peroxisomes as outlined in Fig. 7 [28]. Activation... 

The second category of branched-chain FA consists of the isoprenoid acids, derived from isoprene nnits (see Section 3.5). They are widely distribnted in both terrestrial and marine organisms. Examples include 2,6,10,14-tetramethylpenta-decanoic acid (pristanic acid) and 3,7,11,15-tetramethylhexadecanoic acid (phytanic acid). 

In 1963, Klenk and Kahlke identified the lipid accumulating in Refsum s disease as phytanic acid (3,7,11,15-tetramethylhexadecanoic acid). As a result, phytanic add is probably the best known 3-methyl-branched chain fatty acid. Over the subsequent 30 years, many groups have tried to elucidate the breakdovm of phytanic acid. The presence of the 3-methyl group in ph54anic acid prevents its degradation via P-oxidation, the... 

Refsum disease, also called heredopathia atactica polyneuritiformis, is a rare hereditary neurological disease that is transmitted as an autosomal recessive. It results from the absence of an enzyme (phytanic acid oxidase) which catalyzes the a-oxidation of phytanic acid (3,7,11,15-tetramethylhexadecanoic acid). Because of the methyl side chain in position 3 the j8-carbon oxidation of phytanic acid is blocked and the breakdown of phytanic acid can only start through a-oxidation. The product of the a-oxidation is pristanic... 

Methyl-branched fatty acids need to undergo oxidative decarboxylation via a process called a-oxidation to release the terminal carboxylgroup as CO2. One of the most important physiological 3-methyl-branched fatty acids is phytanic acid (3,7,11,15-tetramethylhexadecanoic acid), long known to accumulate in Refsum disease as well as in other disorders. 

The pathognomonic and consistent finding in serum is the occurrence of 3,7,11,15-tetramethylhexadecanoic acid (phjrtanic acid), as demonstrated by... 

Blood lipids. 4. The isolation of 3, 7,11, 15-tetramethylhexadecanoic acid (phytanic acid) from ox-plasma lipids. Biochem. J. 91, 584 (1964). 

H. Moser, and E. Rossi Refsum s disease (heredopathia atactica polyneuritiformis). An inborn error of lipid metabolism with storage of 3, 7, 11, 15-tetramethylhexadecanoic acid. A review of the clinical findings. Humangenetik 1, 322 (1965 a). 

Kahlke 1964). The 3,7,11,15-tetramethylhexadecanoic acid, which is found in affected individuals, also could be demonstrated in small amounts in the serum of normals and heterozygotes studied (Kahlke 1965). 

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