Conjugated unsaturated fatty adds

What is important though is that the double bonds are separated by one and only one single bond. Remember the unsaturated fatty add, linoleic acid, that you met in Chapter 3 Another fatty acid with even more unsaturation is arachidonic acid. None of the four double bonds in this structure are conjugated since in between any two double bonds there is an sp carbon. This means there is no p orbital available to overlap with the ones from the double bonds. The saturated carbon atoms insulate the double bonds from each other. 

The term conjugated linoleic add (CLA) refers to a mixture of positional and geometric isomers of linoleic add with a conjugated double bond system milk fat can contain over 20 different isomers of CLA. CLA isomers are produced as transient intermediates in the rumen biohydrogenation of unsaturated fatty acids consumed in the diet. However, cis-9, trans-11 CLA, known as rumenic acid (RA), is the predominant isomer (up to 90% of total) because it is produced mainly by endogenous synthesis from vaccenic acid (VA). VA is typically the major biohydrogenation intermediate produced in the rumen and it is converted to RA by A9-desaturase in the mammary gland and other tissues. 

Fatty acids containing acetylenic bonds, double bonds close to the carboxyl group, conjugated unsaturation, or other reducible (e.g., keto) groups rarely add the... 

The sulfite radical is a sulfur-centered radical and would form a S-H bond if it undergoes a hydrogen abstraction reaction. These bonds are weaker than typical C-H bonds and indeed hydrogen abstraction reactions, for example from 2-propanol, have been found to be very slow k < 10 L mol" s ) [53]. SOf does, however, add to unsaturated bonds, not only carbon-carbon double and triple bonds, but also C=S and C=N bonds [68]. The rate constants for the addition of 803" to unsaturated fatty acids were found to increase from about 3x10 L mol" s" for non-conjugated, straight chain fatty acids (linoleate, linolenate, and arachidonate) to about 1 x lO L mol" s for branched chain, conjugated fatty acids (crocin and crocetin) [69]. 

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