Palmitoleate

Palmitic acid, structure of, 1062 Palmitoleic acid, structure of, 1062 PAM resin, solid-phase peptide synthesis and, 1037 Para (m), 519 Paraffin, 91 Parallel synthesis, 586 Parent peak (mass spectrum), 410 Partial charge, 36 Pasteur, Louis, 297, 307... 

Certain long-chain unsaturated fatty acids of metabolic significance in mammals are shown in Figure 23-1. Other C20, C22, and C24 polyenoic fatty acids may be derived from oleic, linoleic, and a-flnolenic acids by chain elongation. Palmitoleic and oleic acids are not essential in the diet because the tissues can introduce a double bond at the position of a saturated fatty acid. 

Figure 23-1. Structure of some unsaturated fatty acids. Although the carbon atoms in the molecules are conventionally numbered—ie, numbered from the carboxyl terminal—the co numbers (eg, co7 in palmitoleic acid) are calculated from the reverse end (the methyl terminal) of the molecules. The information in parentheses shows, for instance, that a-linolenic acid contains double bonds starting at the third carbon from the methyl terminal, has 18 carbons and 3 double bonds, and has these double bonds at the 9th, 12th, and 15th carbons from the carboxyl terminal. (Asterisks Classified as "essential fatty acids.")...

SCDs are a family of microsomal Fe-based metalloenzymes. They act on long-chain saturated acyl CoAs and introduce a ds-double bond at the C-9 or C-10 position. For example, SCDs convert stearic acid into oleic acid, and palmitic acid into palmitoleic acid. Monounsaturated FAs constitute a major component of TGs, cholesteryl esters, and phospholipids. The reaction requires molecular 02 and NADH and generates H20 in the process [3,4]. 

The tuft-forming green alga Cladophora glomerata synthesizes a wide variety of toxic fatty acids, including capric and palmitoleic acids, which have been demonstrated to be insecticidal and allelopathic (Dodds and Gudder 1992). 

Tran. -isomers are much rarer than cis-isomers. Many different positional isomers of monoenoic acids may be present in a single, natural lipid and this is not a comprehensive list. Palmitoleic and oleic acids are quantitatively the commonest unsaturated fatty acids in most organisms. Odd-chain monoenoic acids are minor components of animal lipids but are more significant in some fish and bacterial lipids. 

Additionally, it should be observed that the thermal oxidability and oxidative polymerization of the unsaturated fatty acids follows the trend linolenic > linoleic > oleic > > palmitoleic (Martinenghi, 1963). The oxidation involves, as first step, the abstraction of a hydrogen atom in allylic position to the double bonds. Certainly, this process is favoured in the case of fatty acids with two or more unconjugated double bonds where the formation of a free radical by allylic hydrogen abstraction leads quite necessarily to double bonds slippage with formation of conjugated double bonds ... 

The second family of secreted proteins that is covalently lipidated is the family of Wnt proteins. They are also involved in numerous processes like proliferation of stem cells, specification of the neural crest, and the expanding of specific cell types. The correct regulation of this pathway is important for animal development. Willert and coworkers were the first to isolate an active Wnt molecule. Mass spectroscopy studies carried out with the isolated protein revealed that cysteine 93 is palmitoylated. Mutating this amino acid to alanine led to almost complete loss of the signaling activity. Later in 2006, a second lipidation was found on a serine in Wnt3a. " In this case, the hydroxyl side chain is acylated with palmitoleic acid. This unsaturated fatty acid seems to be crucial for the progression of the protein through the secretory pathway. The attachment of two different lipid chains may therefore serve different functions. ... 

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