Microtubule-stabilizing neuronal protein; GSK3beta-phosphorylated form mimics pathological hyperphosphorylation seen in Alzheimer's and other tauopathies. Recombinant human tag-free Tau-441 was co-expressed with GSK3beta in E. coli cells. The Tau-441 protein was phosphorylated by GSK3beta in vivo and in vitro prior to the final chromatography purification. Molecular Weight ~64-68 kDa. Supplied as sterile 50 mM Tris-HCl pH 7.5, 50-300 mM NaCl, 1 mM DTT, 10-25% glycerol. Store product at –70°C. For optimal storage, aliquot target into smaller quantities. Avoid repeated handling and multiple freeze/thaw cycles.