Lipids functional derivatives

Figure 8.9 Prostaglandins and leukotrienes are potent eicosanoid lipid mediators, derived from phospholipase-released arachidonic acids, that are involved in numerous homeostatic biological functions and inflammation. They are generated by cyclooxygenase isozymes and 5-lipoxygenase, respectively, and their biosynthesis and pharmacological actions are inhibited by clinically relevant nonsteroidal anti-inflammatory drugs.

Surfactants, or surface active agents, occur widely in nature where they are usually classified as lipids. They have been used for over 1000 years in everyday applications as emulsifiers in cleaning and in foods. Their functionality derives from a unique feature in the molecular structure they are molecules that consist of two distinctly different regions. One is a polar (hydrophilic) moiety termed the head group, and the other a nonpolar (hydrophobic) part, referred to as... 

Leukotrienes (LTs) are lipid mediators derived enzymatically from arachidonic acid. Structurally, these eicosanoids contain a conjugated triene functionality. LTB4 and LTC4 are the two important leukotrienes. Mass spectrometry has played... 

This chapter summarizes the state of knowledge abont protein lipoxidation, focusing on the chemistry of lipid peroxidation-derived aldehydes and their adducts with amino acid residnes. In addition, the recent findings on ligand function of lipoxidation products are also reviewed. 

Prostaglandin (Section 27.4) A lipid derived from arachi-donic acid. Prostaglandins are present in nearly all body tissues and fluids, where they serve many important hormonal functions. 

Fig. 3-12 Lipids consist of a triglyceride, three fatty acids such as those in (a) joined to glycerol (b). Other lipids include other functional groups such as phosphate derivatives (c). (Reprinted with permission from W. K. Purves and G. H. Orians, "Life The Science of Biology," pp. 63-81, Copyright 1987 by Sinauer Associates, Inc., Simderland, MA.)...

While the fluid mosaic model of membrane stmcture has stood up well to detailed scrutiny, additional features of membrane structure and function are constantly emerging. Two structures of particular current interest, located in surface membranes, are tipid rafts and caveolae. The former are dynamic areas of the exo-plasmic leaflet of the lipid bilayer enriched in cholesterol and sphingolipids they are involved in signal transduction and possibly other processes. Caveolae may derive from lipid rafts. Many if not all of them contain the protein caveolin-1, which may be involved in their formation from rafts. Caveolae are observable by electron microscopy as flask-shaped indentations of the cell membrane. Proteins detected in caveolae include various components of the signal-transduction system (eg, the insutin receptor and some G proteins), the folate receptor, and endothetial nitric oxide synthase (eNOS). Caveolae and lipid rafts are active areas of research, and ideas concerning them and their possible roles in various diseases are rapidly evolving. 

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