CHOLINE

Publisher Summary This chapter discusses the isolation, physical and chemical properties, and synthesis of choline. Choline is widely distributed in biological materials as free choline, acetylcholine, and more complex phospholipids and their metabolic intermediates. Choline is characterized by a trimethyl quaternary nitrogen. Choline has been obtained from a variety of tissues and fluids since their original isolations. The earliest methods employed for isolating choline from biological extracts were dependent on the use of various sensitive though nonspecific precipitants. Choline is precipitated from alcoholic solutions as the double salt of platinum, gold, or mercury chlorides. The periodide separation is generally considered one of the most sensitive methods of precipitating choline. The chapter describes the industrial preparation of choline. The reaction between trimethylamine and either ethylene chlorohydrin or ethylene oxide is commonly used in the manufacture of choline. The studies on choline and its derivatives have emphasized the biochemical importance of these compounds as structural components of tissues, as intermediates in vital metabolic reactions, and as specific chemical reactants of marked biological potency.