Engineering of functional supramacromolecular complexes of proteins (enzymes) using reversed micelles as matrix...

The size of the inner water cavity of reversed micelles formed in a triple system 'water-surfactant-organic solvent' can be widely varied by changing the degree of surfactant hydration. This gives grounds to use reversed micelles as matrix microreactors for the design of supramolecular complexes of proteins. Using ultracentrifugation analysis, it has been demonstrated that the oligomeric composition of various enzymes (ketoglutarate dehydrogenase, alkaline phosphatase, lactic dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase) solubilized in reversed micelles of Aerosol OT [sodium bis(2-ethylehexyl)sulfosuccinate] in octane changes upon variation of the degree of hydration. An oligomeric complex forms under conditions when the radius of the micelle inner cavity is big enough to incorporate this complex as a whole. At lower degrees of hydration the micelles 'uncouple' such complexes to their components. The catalytic properties of various oligomeric complexes have been studied. Possibilities of using reversed micelles for the separation of subunits of oligomeric enzymes under non-denaturating conditions have been demonstrated. In particular, the isolated subunits of alkaline phosphatase, lactic dehydrogenase and glyceraldehyde-3-phosphate have been found to be active in Aerosol OT reversed micelles. The dependences of the catalytic activity of oligomeric enzymes represent saw-like curves. The maxima of the catalytic activity observed at these curves relate to the functioning of various oligomeric forms of an enzyme. The radii of the micelle inner cavity under conditions when these maxima are observed correlate with the linear dimensions of the enzyme oligomeric forms. Correlation of the position of a maximum with the shape of an oligomeric complex is discussed.