Double bond oxidation of unsaturated fatty acids

1988 ◽  
Vol 65 (4) ◽  
pp. 611-615 ◽  
Author(s):  
B. Zaldman ◽  
A. Kisilev ◽  
Y. Sasson ◽  
N. Garti
Keyword(s):  
Fatty Acids ◽  
Double Bond ◽  
Unsaturated Fatty Acids

Structural Homogeneity in Unsaturated Fatty Acids of Marine Lipids. A Review

1964 ◽  
Vol 21 (2) ◽  
pp. 247-254 ◽  
Author(s):  
R. G. Ackman
Keyword(s):  
Fatty Acids ◽  
Double Bond ◽  
Polyunsaturated Fatty Acids ◽  
Chain Length ◽  
Unsaturated Fatty Acids ◽  
Analytical Data ◽  
Double Bonds ◽  
Marine Origin ◽  
Methyl Group ◽  
Marine Lipids

Consideration of recent analytical data supports the conclusion that the longer-chain polyunsaturated fatty acids of marine origin are all structurally homogeneous in that the double bonds are cis, the double bonds methylene interrupted, and that, with the exception of the C16 chain length, the ultimate double bond will normally be three, six or nine carbon atoms removed from the terminal methyl group.

Location of double-bond position in unsaturated fatty acids by negative ion MS/MS

1983 ◽  
Vol 105 (16) ◽  
pp. 5487-5488 ◽  
Author(s):  
Kenneth B. Tomer ◽  
Frank W. Crow ◽  
Michael L. Gross
Keyword(s):  
Fatty Acids ◽  
Double Bond ◽  
Unsaturated Fatty Acids ◽  
Double Bond Position ◽  
Negative Ion

Cyclopropane ring formation in membrane lipids of bacteria

1997 ◽  
Vol 61 (4) ◽  
pp. 429-441 ◽  
Author(s):  
D W Grogan ◽  
J E Cronan
Keyword(s):  
Fatty Acids ◽  
Double Bond ◽  
Lipid Bilayers ◽  
Unsaturated Fatty Acids ◽  
Membrane Lipids ◽  
Cyclopropane Ring ◽  
Saturated Fatty Acids ◽  
Physiological Role ◽  
Phospholipid Bilayer ◽  
Valuable Insight

It has been known for several decades that cyclopropane fatty acids (CFAs) occur in the phospholipids of many species of bacteria. CFAs are formed by the addition of a methylene group, derived from the methyl group of S-adenosylmethionine, across the carbon-carbon double bond of unsaturated fatty acids (UFAs). The C1 transfer does not involve free fatty acids or intermediates of phospholipid biosynthesis but, rather, mature phospholipid molecules already incorporated into membrane bilayers. Furthermore, CFAs are typically produced at the onset of the stationary phase in bacterial cultures. CFA formation can thus be considered a conditional, postsynthetic modification of bacterial membrane lipid bilayers. This modification is noteworthy in several respects. It is catalyzed by a soluble enzyme, although one of the substrates, the UFA double bond, is normally sequestered deep within the hydrophobic interior of the phospholipid bilayer. The enzyme, CFA synthase, discriminates between phospholipid vesicles containing only saturated fatty acids and those containing UFAs; it exhibits no affinity for vesicles of the former composition. These and other properties imply that topologically novel protein-lipid interactions occur in the biosynthesis of CFAs. The timing and extent of the UFA-to-CFA conversion in batch cultures and the widespread distribution of CFA synthesis among bacteria would seem to suggest an important physiological role for this phenomenon, yet its rationale remains unclear despite experimental tests of a variety of hypotheses. Manipulation of the CFA synthase of Escherichia coli by genetic methods has nevertheless provided valuable insight into the physiology of CFA formation. It has identified the CFA synthase gene as one of several rpoS-regulated genes of E. coli and has provided for the construction of strains in which proposed cellular functions of CFAs can be properly evaluated. Cloning and manipulation of the CFA synthase structural gene have also enabled this novel but extremely unstable enzyme to be purified and analyzed in molecular terms and have led to the identification of mechanistically related enzymes in clinically important bacterial pathogens.

Characterization of branched and unsaturated fatty acids in Mycobacterium vaccae strain JOB5

1975 ◽  
Vol 21 (4) ◽  
pp. 510-512 ◽  
Author(s):  
D. H. King ◽  
J. J. Perry
Keyword(s):  
Fatty Acids ◽  
Double Bond ◽  
Unsaturated Fatty Acids ◽  
Mycobacterium Vaccae ◽  
Mass Spectral ◽  
Cellular Fatty Acids ◽  
Branched Chain ◽  
Chain Synthesis ◽  
Chromatographic Mass

After growth of Mycobacterium vaccae strain JOB5 on acetate or propane, the cellular fatty acids were isolated and identified by a combination of gas-chromatographic, mass-spectral, and chemical means. The fatty acids ranged from C12 to C19 and were a mixture of saturated, monounsaturated, and methyl-branched components. The double bond was in the Δ9 position in the C15 to C18 unsaturated acids. The single methyl branch was located on the C10 position of Br-C17, Br-C18, and Br-C19 fatty acids. Branched-chain synthesis occurs at the expense of an unsaturated precursor fatty acid; the double bond serves as the site of methylation. Results suggest that S-adenosylmethionine is the methyl donor involved.

Geometric isomerism in some unsaturated aliphatic ketones

1955 ◽  
Vol 8 (4) ◽  
pp. 506 ◽  
Author(s):  
HH Hatt ◽  
JA Lamberton
Keyword(s):  
Fatty Acids ◽  
High Temperature ◽  
Double Bond ◽  
Ethyl Ester ◽  
Oxide Catalyst ◽  
Unsaturated Fatty Acids ◽  
Sodium Ethoxide ◽  
Cyclic Ketones ◽  
Metallic Oxide ◽  
Aliphatic Ketones

If ketones are prepared by heating unsaturated fatty acids at a high temperature in the presence of a metal or metallic oxide catalyst, some stereoisomeric change and movement of the double bond accompany ketonization. The ketones, oleone and erucone of the cis-cis-class, described in the literature as products of reactions of this kind, are shown to have been mixtures of isomers with trans-trans-forms predominating. Oleone and erucone, containing no detectable amounts of trans-material can be prepared either from the corresponding acyl chloride and triethylamine, or by condensation of the methyl or ethyl ester of the appropriate acid in xylene using sodium ethoxide as catalyst. These ketones are readily converted to the tetrahydroxy ketones and thence by oxidation to ketodibasic acids, useful as intermediates for the preparation of cyclic ketones.

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