The pronunciation of the compound reflects its origin and first isolation from sugar beets (Beta vulgaris subsp. vulgaris), and does not derive from the Greek letter beta (?), however, it often is pronounced beta-INE or BEE-tayn.[1]
In biological systems, many naturally occurring betaines serve as organic osmolytes, substances synthesized or taken up from the environment by cells for protection against osmotic stress, drought, high salinity, or high temperature. Intracellular accumulation of betaines, non-perturbing to enzyme function, protein structure, and membrane integrity, permits water retention in cells, thus protecting from the effects of dehydration. It is also a methyl donor of increasingly recognised significance in biology.
Betaine is used to treat homocystinuria.