Cryoenzymology in aqueous media: Micellar solubilized water clusters.

Amphiphilic compounds dissolved in nonpolar organic solvents form inverted micelles whose aqueous centers can solubilize relatively large amounts of enzymes. The solutions are homogeneous and optically transparent and have low viscosity and freezing points; they provide unique and favorable systems to perform the main cryoenzymologic studies previously carried out in mixed solvents. The preparation and properties of such micelles are described. The absorbance spectra of cytochrome c at various temperatures from -38 degrees C to 20 degrees C are given. The pH dependence of trypsin-catalyzed hydrolysis of benzoylarginine ethyl ester in inverted micelles, as well as kinetic properties and activation energy, is described. Some problems are analyzed.