Molecular Mass: HMGB1 consists of 215 amino acid residues and has a calculated molecular mass of approximately 24.8 kDa. It migrates at a position of approximately 30 kD in SDS-PAGE gels, possibly because of the unusual number of positively charged amino acids it contains. Structure: HMGB1 consists of two fairly rigid, L-shaped DNA-binding domains, each referred to as a ‘HMG box’, and an unstructured tail that ends with 30 consecutive negatively charged amino acids. Purity: The purified protein is >95% homogeneous (electrophoresis and mass spectrometry). It contains no nucleic acids, nor IL-1beta. Buffer: 50 mM HEPES-Na pH 7.9, 500 mM NaCl, 0.5 mM DTT. Storage: the protein is shipped lyophilized. Once resuspended can be stored frozen at -20°C. To avoid cysteine oxidation, DTT 0.5mM is added during protein purification. This product is intended for research only, and cannot be used on humans.