A betaine
in chemistry is any neutral chemical compound with a positively charged
cationic functional group. For example, a quaternary ammonium or phosphonium
cation which bears no hydrogen atom and
with a negatively charged functional group such as a carboxylate group which
isn't adjacent to the cationic site possibly.Therefore, a betaine may be a specific
kind of zwitterion.
In biological systems, a great many of betaines serve as organic osmolytes,
substances synthesised or taken up from the environment by cells for protection
against osmotic stress, drought, high salinity or high temperature.
