[New data on the molecular heterogeneity of brain-specific protein S100]

A comparative study of distribution of labeled products of endogenous limited proteolysis of the "major" (MF) and "minor" (S100-26) fractions of proteins S100 from rat brain by ion-exchange chromatography was carried out with a view of testing the hypothesis on the formation of proteins S100 molecular associates as a possible cause of molecular weight heterogeneity of proteins S100. There is evidence that proteins S100-MF and S100-26 are different species of brain-specific S100 proteins. The experimental results also suggest that the brain-specific proteins S100-MF and S100-26 are adsorbed both by glial cells and by neurons. Some physico-chemical properties of peptide proteolytic products of various species of proteins S100 were investigated.