| Abstract: | Using ultracentrifugation, the systems of reversed micelles of aerosol OT in octane containing solubilized protein (alpha-chymotrypsin, lysozyme, trypsin, egg albumin, alcohol dehydrogenase from horse liver and gamma-globulin) were studied. The changes in the sedimentation coefficients of reversed micelles during incorporation of the protein are correlated (within a wide range of experimental conditions, e. g. degree of surfactant hydration or protein concentration) exclusively with the molecular weight of the solubilized protein. The simplest solubilization model, according to which the protein molecule is incorporated into the inner cavity of the reversed micelle at the stoichiometric ratio of 1 : 1, which does not affect the external sizes of the reversed micelle, has been proposed. Using alpha-chymotrypsin as an example, the conditions, under which the sedimentation properties of the systems deviate from this model, have been found. These deviations occurred at sufficiently low degrees of the surfactant hydration, when the inner cavity of the reversed micelle is smaller than the effective size of the solubilized protein molecule. In the latter case the protein forms a new micelle of necessary (i. e. larger) size. Since the hydrated micelle can be regarded as an elementary (30-100 A) fragment of biomembranes, the results obtained should be taken into consideration when analyzing the structural organization and functioning of the latter. |
