Help: what is glycl betaine?

the End jgraham at
Fri Oct 15 12:56:18 EST 1993

What you want is the osmolyte "glycine betaine" sometimes called
just "betaine". Not only do people refuse to pronounce it correctly,
apparently they like to give it a whole new name, as if it is something
they have just discovered (N-trimethyl glycine).

Such "compatible solutes" are know to accumulate in the cytoplasmic
cell pools of bacterial and plant cells under conditions of osmotic
stress. Theoretically, they effect t he hydration shell surrounding
proteins by being excluded form the protein solvent inferface. Because
a random distribution of osmolyte is energetically favored, the 
system moves towards minimizing the excluded region, the protein-
solvent interface. This tends to favor protein-protein interactions,
including subunit assembly and folding.

This secondary role may be be as important as the primary role of osmolytes
in creating a more suitable osmotic balance between the cell and its 
environment as it conteracts the destabablizing effect of increased 
concentration of charged solutes in the cytoplasm.

J. Graham
Biology and Chemistry Departments
Indiana University Bloomington

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