COMPETITIVE REACTIONS IN SOLUTIONS OF PROTEIN-POLYELECTROLYTE COMPLEXES

The ability of negatively charged globular proteins (bovine serum albu min, trypsin soy inhibitor) to interact with linear synthetic polycati ons (poly-N-ethyl-4-vinylpyridinium bromide, poly-N,N-dimethyldiallyla mmonium chloride) and to form negatively charged water-soluble complex es, in which the protein is a lyophilizing component has been revealed . The complexes are formed if the total number of the protein negative charges exceeds the total number of the polycation positive charges i n the mixture. The composition of the complexes remains virtually unch anged and corresponds to one chain of polycation and only such number of protein globules that provides the solubility of the complex partic le as a whole. The competitive reaction accompanied with transfer of t he protein globule from one complex species to another one was studied by fluorescence quenching technique. It is shown that the rate of the reaction is quite high even in dilute aqueous solution and becomes hi gher after addition of salt (NaCl). As it follows from the results obt ained these model systems obey the basic principles established for in terpolyelectrolyte reactions in solutions of oppositely charged flexib le-chain synthetic polyions.