Аннотация:The interaction of partially N-betainated oligochitosans (Q-CHI) with bovine serum albumin (BSA) in alkalescent media is described. It is shown that Q-CHI forms complexes with BSA in solutions with pH 7.4. Isothermal titration calorimetry in the buffers with different ionization heats reveals a significant contribution of electrostatic forces to the binding and an additional ionization of primary amino groups of Q-CHIs due to the proton transfer from the buffer substance. Circular dichroism study shows that the secondary structure of BSA in soluble complexes remains unaltered.