Sphingolipids definition

Lipids are far more diverse chemically than other typical biomolecules such as amino acids, carbohydrates, and nucleotides. The definition of lipids includes simple fatty acids and their glycerol esters, sterols such as cholesterol, and phospholipids, sphingolipids, and cerebrosides. Lipids are generally defined by their common hydrophobic character, which makes them soluble in organic solvents such as chloroform. Virtually all lipids also have a hydrophilic group, which makes them surface active. 

The term lipid is frequently used to denote a wide variety of natural products fatty , oily or waxy substances of animal and vegetable origin that are easily soluble in organic solvents readily satisfy this loose definition. Thus, such diverse compounds as fatty acids and their derivatives, triglycerides, sterols, phosphatides and sphingolipids, carotenoids, bile acids, vitamins A, D, E, and K, long-chain alcohols, terpenes, etc., may be included. Studies of these substances by GC are indeed numerous a comprehensive survey of this field is beyond the scope of this... 

Lipids are defined as water-insoluble compounds extracted from living organisms by weakly polar or nonpolar solvents. The definition is based on a physical property in contrast to the definitions of the other basic building blocks in this chapter (proteins, carbohydrates, and nucleic acids), which are based on chemical stracture. Consequently the term lipid covers a stmcturally diverse group of compounds including/afiy acids, glycerolipids, sphingolipids, terpenes, steroids, and carotenoids. There is no universally accepted scheme for their classification. 

It is amazing tiiat such a simple molecule has for decades and several generations of talented biochemists resisted definition. Carter et al. have also introduced the term sphingolipids to designate lipids derived from the parent base sphingosine." In most textbooks, the way sphingosine is represented makes it difficult to memorize. However, following the step-by-step procedure described in Fig. 1.18 makes it clearer. 

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