S100a0 (αα) Protein: Distribution in Muscle Tissues of Various Animals and Purification from Human Pectoral Muscle

When the concentrations of alpha-S100 (alpha subunit of S100 protein) and beta-S100 (beta subunit) proteins in various tissues of human and rat were determined by the immunoassay method, immunoreactive beta-S100 was present at high levels in the CNS, adipose tissue, and cartilaginous tissue. In contrast, the alpha-S100 was found in the heart and skeletal muscles at concentrations much higher than in the CNS. The concentration of alpha-S100 protein was also high in the heart and skeletal muscles of bovine, porcine, canine, and mouse. Since beta-S100 protein levels in those tissues were low, it was suggested that S100 protein in the muscle tissues is present mainly as the alpha alpha form (S100a0 protein). To confirm the above findings, immunoreactive alpha-S100 protein was purified from human pectoral muscle by employing column chromatographies with butyl-Sepharose, diethylaminoethyl (DEAE)-Sepharose, Sephadex G-75, and finally with an anion-exchange Mono Q column in a HPLC system. The elution profile of alpha-S100 protein from the Mono Q column suggested some heterogeneity of the final preparation. However, each of these fractions traveled with a single band at a position similar to that of bovine S100a0 protein on slab-gel electrophoresis. The amino acid composition of the final preparation was very similar to the composition of bovine S100a0 protein. The purified alpha-S100 protein was eluted from a gel-filtration column (Superose 12) in the same fraction as bovine S100a0 protein.(ABSTRACT TRUNCATED AT 250 WORDS)