[Heterogeneity of neurospecific protein S-100]

Protein S-100 specific for the nervous system was isolated from the bull cerebral hemispheres by the Steward method and antiserum monospecific to it was obtained. In immunoelectrophoretical study of the initial brain extract with antiserum detected the paired line of precipitation consisting of two arcs in the zone of prealbumins and alpha2-globulins of the the serum, and that with purified protein fraction showed only one arc corresponding to the prealbumin component. The purified protein S-100 fraction in agar gel is divided into a series of prealbumin electrophoretic zones, with a pre-protein locating chiefly in the most mobile zone. It is established that heterogeneity of protein S-100 with electrophoresis in agar gel and immunophoresis is due to the presence of calcium ions in the systems. In the presence of 1 mM EDTA solution the one or two closely located prealbumin zones of purified protein S-100 migrates. The obtained monospecific antiserum made it possible to establish that two-fractional antigen A detected previously by the heterogenic antisera is protein S-100.