Essential role of w/o microemulsion structure on catalytic activity of entrapped proteins studied by small-angle X-ray scattering and circular dichroism

For understanding the mechanism of enhancement of catalytic activity of proteins in w/o microemulsions, it is very important to clarify a relation between structural characteristics of w/o microemulsion and occluded protein. We have studied the structure and catalytic activity of two different types of bovine serum albumins occluded in biological solvent / sodium bis(2-ethylhexyl)sulfosuccinate (AOT) / 2,2,4-trimethylpentane (isooctane) microemulsions. The secondary structures of the albumins both in AOT w/o microemulsions and in aqueous buffer solvents containing AOT have been measured by using circular dichroism. The structures of AOT microemulsions occluding the proteins have been studied by using synchrotron radiation small-angle X-ray scattering. We will show the detailed relation between the microemulsion structure and the catalytic activity of the proteins.