The Amino‐Acid Sequence of the α Subunit in Bovine Brain S‐100a Protein

Abstract

The brain specific S-100 protein is a mixture of two components S-100a and S-100b with a subunit composition αβ or β₂ respectively. The amino acid sequence of the β subunit has been previously determined. This paper presents the sequence of the α subunit in the S-100a protein. The α subunit consists of 93 amino-acid residues and has a relative molecular mass of 10400. The sequence shows extensive homology (58%) with that of the β-subunit and shares an apparent calcium binding site in the C-terminal half of the molecule, suggesting a close evolutionary relationship between these subunits.