Hsp105 is a mammalian member of the HSP105/110 family, a diverged subgroup of the HSP70 family. HSP105 exists as two isoforms, alpha and beta. Hsp105 alpha associates with Hsp70/Hsc70 as complexes in vivo and regulates the chaperone activity of Hsp70/Hsc70 negatively in vitro and in vivo. Recombinant His tagged HSP105 was expressed in E.coli and purified by using conventional chromatography techniques.