Biomolecules Lipids and Their Metabolism

Hydroxyacyl-CoA dehydrogenase catalyzes the oxidation of a /3-hydroxyacyl CoA to a /3-ketoacyl CoA during fatty-acid metabolism. 

Lagniappe—Saturated Fats, Cholesterol, and Fleart Disease 

Lipids are naturally occurring organic molecules that have limited soluhilLty in water and can be isolated from organisms by extraction with nonpolar organic solvents. Fats, oils, waxes, some vitamins and hormones, and most nonprotein cell-membrane components are examples. Note that this definition differs from the sort used for carbohydrates and proteins in that lipids are defined by a physical property (solubility) rather than by structure. Of the many kinds of lipids, we ll be concerned in this chapter only with a few triacylglycerols, terpenoids, and steroids. 

Lipids are classified into two broad types those like fats and waxes, which contain ester linkages and can be hydrolyzed, and those like cholesterol and other steroids, which don t have ester linkages and can t be hydrolyzed. 

We ve now covered two of the four major classes of hiomolecules—proteins and carbohydrates—and have two remaining. We ll cover lipids, the largest and most diverse class of hiomolecules, in this chapter, looking both at their structure and function and at their metaholism. 

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Protein kinases and phosphatases play vital roles in intracellular signaling pathways and in the integration and control of major cellular processes. Kinases and other phosphoryl group transferases are essential in the metabolism of lipids, nucleotides, and other small biomolecules. The use of SBDD methods on such targets has expanded as more of their X-ray structures have been solved, and will continue to grow as more targets are validated for their involvement in human diseases. 

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