Characterization of Human Brain S100 Protein Fraction: Amino Acid Sequence of S100β

Publisher Website
Google Scholar
Abstract
Two major components of human brain S100 fraction were purified by HPLC [high performance liquid chromatography] and an amino acid sequence was elucidated for the S100.beta. component. Human S100 proteins showed absorption spectra and amino acid compositions similar to S100.alpha. and S100.beta. from bovine brain. The relative amounts of the human proteins were 4% S100.alpha. and 96% S100.beta. by weight, while the bovine protein distribution was 47% S100.alpha. and 53% S100.beta. by weight. An amino acid sequence of human S100.beta. was established by analysis of overlapping fragments generated by cyanogen bromide and trypsin cleavage. Three amino acid sequence differences between the human bovine S100.beta. were found at residues 7, 62 and 80. These differences were chemically conservative and compatible with minimum single base changes in the codon structures. S100.beta. is a conserved protein among mammals and provide the necessary foundation for current clinical studies.