The amino-acid sequence of S-100 protein (PAP I-b protein) and its relation to the calcium-binding proteins.

The amino acid sequence of a brain-specific protein, S-100, has been determined by the analysis of four cyanogen bromide peptides and fourteen tryptic peptides derived from the protein. The protein chain consists of 91 amino acid residues and has a molecular weight of 10507. The sequence shows regions of stong clustering of hydrophobic, basic and acidic amino acids, with an apparent calcium-binding site in the acidic cluster.