Use of hydrated reversed micelles of surfactant in organic solvent for stabilization of individual oligomeric forms of uridine phosphorylase from Escherichia coli K-12.

The catalytic activity of uridine phosphorylase from Escherichia coli K-12 entrapped in hydrated reversed micelles of aerosol OT (AOT) in octane has been studied as a function of the degree of hydration of the micelles. It was shown that the catalytic activity of uridine phosphorylase reached maximum values at [H2O/[AOT] ratios equal to 8.4, 12.9, 16.1 and 18.6. Based on the sedimentation data the conclusion has been made that the maxima of the catalytic activity correspond to the monomeric, dimeric, trimeric and tetrameric forms of the enzyme. The measurements of the rate of the enzymatic reaction catalyzed by uridine phosphorylase entrapped in hydrated reversed micelles at various concentrations of AOT indicate that the monomeric enzyme form, in contrast to the trimeric and tetrameric forms, exhibits the membranotropic properties.