Abstract: The effect of guanidine hydrochloride on the activity of Bovine Pancreatic ribonuclease Asolubilized in reverse micelles formed in cyclohexane by dodecylammonium butyrate(DAB) and water has been investigated using cytidine 2',3',-phosphate as the substrate, It was noted that the enzyme entrapped in DABreverse micelles maintained more activity compared to aqueous solution at the same guanidine concentration, because protein molecule was constrained by the micellar enviroment into a conformation close to the native.Fluorescence studies showed that the degree of polarization of protein fluorescence in the micelles increased with respect to that in water which also suggested a lower mobility of the protein.

Key words: Reverse micelles, RNAse A, Guanidine hydrochloride, Enzymatic activity