Comparison of DMSO-induced denaturation of hen egg-white lysozyme and bovine α-lactalbumin

By using both wide-angle neutron and small-angle X-ray scattering techniques, we have studied the denaturation processes of hen egg-white lysozyme (HEWL) and bovine ol-lactalbumin (BLA) in dimethyl sulfoxide (DMSO)/water mixtures. Although these proteins are known to be highly homologous, the present results indicate that the structure of BLA is liable to be destroyed by the addition of DMSO in comparison with the case of HEWL. DMSO-induced denaturation is suggested to relate to the collapse of hydration shell surrounding the protein surface. (C) 1999 Elsevier Science Ltd. Ail rights reserved.