[Heterogeneity of brain-specific proteins of S100 type]

A procedure for preparative separation of proteins from bovine brain precipitated in a saturated solution by ammonium sulfate (pH 4.0) and remaining in the supernatant is described. It was shown that not less than 22 fractions (up to 28 fractions considering the "equivocal" reaction) produce different responses to the antiserum against the major protein, i.e. S100.