Structural changes of a protein bound to a polyelectrolyte depend on the hydrophobicity and polymerization degree of the polyelectrolyte

Influence of polyelectrolytes of different chemical structure and degree of polymerization on aggregation and denaturation of the oligomeric enzyme glyceraldehyde-3-phosphate dehydrogenase has been studied to ascertain molecular characteristics of the polymer chains providing the efficient prevention of aggregation of the enzyme without drastic changes in its structure and catalytic activity. The best polymers meeting these requirements were found to be hydrophilic high-molecular-weight polyelectrolytes forming stable complexes with the enzyme. The revealed pronounced negative effect of short polymer chains on the enzyme must be taken into account in the design of protein-polyelectrolyte systems by using thoroughly fractionated polymer samples containing no admixture of charged oligomers.