Bovine Brain S100 Proteins: Separation and Characterization of a New S100 Protein Species

Abstract
Three S100 protein species (S100a, S100b, S100a'') were purified from bovine brain using a modification of standard preparative methods. A higher yield for each protein was obtained at the last separation step. Characterization by urea/sodium dodecyl sulfate/polyacrylamide gel electrophoresis, UV absorption spectra and fluorescence parameters, provided evidence of a new tryptophan-containing S100 protein called S100a'', which exhibits, as S100a and S100b, the properties of a Ca2+ binding protein.