Different recognition by clostripain of myelin basic protein in the lipid-free and lipid-bound forms

Different proteolytic enzymes were tested for their ability to degrade the myelin basic protein of the central nervous system, purified in two different forms, the lipid-free form and the lipid-bound form. As shown by SDS gel electrophoresis only clostripain, a thiol protease, was able to distinguish between the two MBPs since it degraded MBP only in the lipid-free form. The failure to degrade lipid-bound MBP by clostripain could not be ascribed to the presence of lipids, since the other proteolytic enzymes tested degraded both MBPs independently from lipids giving fragments with different size. These results may be related to different conformations of MBPs possibly relevant for the study of myelin structure and antigenic properties of the protein.