USE OF HYDRATED REVERSED MICELLES OF SURF ACTANT 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 oc tane has been studied as a function of the degree of hydration of mice lles. It was shown that the catalytic activity of uridine phosphorylas e reaches maximum values at ratios [H2O]/[AOT] equal to 8.4; 12.8; 16. 1, and 18.6. On the basis of sedimentation data the conclusion has bee n made that the maxima of the catalytic activity correspond to the mon omeric, dimeric, trimeric, and tetrameric forms of the enzyme. The mea surements of the rate of the enzymatic reaction catalyzed by uridine p hosphorylase entrapped in hydrated reversed micelles at various concen trations of AOT indicate that the monomeric enzyme form, in contrast t o the trimeric and tetrameric forms, ehxibits the membranotropic prope rties.