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natural compounds of the complex lipid group. They are widely distributed in plant and animal organisms as components of biological membranes. Nerve tissue is particularly abundant in cephalins (cephalins were first isolated from the cerebrum).
Cephalin molecules are formed from glycerol, fatty acids, phosphoric acid, and aminoethyl alcohol (ethanolamine phosphatides) or serine (serine phosphatides) radicals. The presence of ionized (neutral pH value) phosphoric acid and amine radicals gives cephalins a polar character and to a great extent determines their chemical and functional properties. Individual cephalins differ from one another by the nature of their fatty-acid content (as a rule, one fatty acid is unsaturated). The term “cephalins” is primarily used to designate unrefined fractions of corresponding phospholipids and not individual chemical substances.