Enzyme activities in concentrated solutions of glycinebetaine and other solutes.

The activities of a number of enzymes in concentrated solutions of glycinebetaine and other solutes have been studied. Glycinebetaine, in contrast to electrolytes such as NaCl, was found to be noninhibitory up to 500 mM. This is compatible with the postulated role of glycinebetaine in cytoplasmic osmoregulation. Partial protection against NaCl inhibition was afforded by glycinebetaine in some cases. More detailed studies on glycinebetaine -NaCl-enzyme interactions were carried out using malate dehydrogenase (decarboxylating) from Hordeum vulgare.