Proline, Betaine and Other Organic Solutes protect Enzymes against Heat Inactivation

Abstract

Proline and betaine, in a concentration-dependent manner, protect several different enzymes with a wide range of thermal sensitivities, and from different sources, against the in vitvo inactivating effects of heat. Since a number of solutes (D-proline, hydroxyproline, glycine, valine and glycerol), in addition to proline and betaine, demonstrate this effect, it is concluded that the interaction between solute and enzyme protein is a general one with respect to both effector and receptor molecules. The nature of the response is unknown, although it may be related to the maintenance of conformational characteristics and integrity of the proteins by the solutes.