Fatty acid desaturases: Selecting the dehydrogenation channel

Desaturation (O 2-dependent dehydrogenation) of long chain fatty acyl derivatives is a ubiquitous biotransformation which generates a wide variety of oxidized lipidic natural products with important biological properties. Recent advance

Exotic biomodification of fatty acids

Many biotransformations of mid- to long chain fatty acyl derivatives are intrinsically interesting because of their high selectivity and novel mechanisms. These include one carbon transfer, hydration, isomerization, hydrogenation, ladderane and hydrocarbon formation, thiolation and various oxidative transformations such as epoxidation, hydroxylation and desaturation. In addition, hydroperoxidation of polyunsaturated fatty acids leads to a diverse array of bioactive compounds. The bioorganic aspects of selected reactions will be highlighted in this review; 210 references are cited

Catalytic diversity of fatty acid desaturases

The highly selective oxidation chemistry carried out by fatty acid desaturases is a potentially important source of novel biocatalytic activity. Recent progress in the mechanistic understanding of this set of reactions will help to guide ongoing protein engineering experiments designed to modify desaturases for specific requirements

Deciphering the cryptoregiochemistry of oleate Δ12 desaturase: A kinetic isotope effect study

The intermolecular primary deuterium isotope effects on the individual C-H bond cleavage steps involved in linoleic acid biosynthesis were determined using a suitably transformed strain of Saccharomyces cerevisiae containing a functional oleate Δ12 desaturase from Arabidopsis thaliana. Mass spectral analysis of the methyl 7-thialinoleate fraction obtained from competition experiments involving methyl 7-thiastearate, methyl [12,12-2H2]-7-thiastearate and methyl [13,13-2H2]-7-thiastearate showed that cleavage of the C12-H bond is very sensitive to isotopic substitution (k(H)/k(D) = 7.3 ± 0.4) while a negligible isotope effect (k(H)/k(D) = 1.05 ± 0.04) was observed for the C13-H bond breaking step. This result strongly suggests that the site of initial oxidation for Δ12 desaturation is at C-12. The possible relationship between castor oleate 12-hydroxylase and microsomal Δ12 oleate desaturases is discussed in the context of a common mechanistic paradigm. Our methodology may be also be useful in deciphering the cryptoregiochemistry of other desaturase systems

Stereochemical analysis of thiosugar sulfoxides using (S)-α-methoxyphenyl acetic acid

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Stereochemical analysis of d-glucopyranosyl-sulfoxides via a combined NMR, molecular modeling and x-ray crystallographic approach

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