Effect of pH on Albumin Binding with Hydrophobic Porphyrins

The behavior of bovine serum albumin as a function of the pH of the medium and the presence in the test systems of symmetrical and asymmetrical hydrophobic porphyrins was investigated. It was established that 4-[(tert-butoxycarbonylamino)acetamido]phenyl group favors stronger protein binding to porphyrin, and this effect enhances in an alkaline medium. Solubilization of protein by porphyrins leads to the fact that the particles are spherical in solution, the hydrodynamic radius of the protein globule reduced in an alkaline medium but in neutral medium, in contrast, increases. By IR spectroscopy it was shown that beta-structuring and the proportion of disordered coils of the polypeptide chain in an alkaline medium increases, because the complexability of the protein towards porphyrin is changes.