HSP 90 is a human heat shock protein. In response to adverse change in their environment, cell from all organisms increase the expression of a class of proteins referred to as heat shock or stress protein. The Hsp90, a highly conserved stress-induced protein, is abundantly expressed in most tissues under nonstress conditions and is required for eukaryotic cell viability. Hsp90 is primarily a cytoplasmic protein and its function remains unknown. It exists in a dimeric form and has been observed to bind to several other cellular proteins such as retro-virus kinases, steroid receptor, heme-regulated protein kinase, actin and tubulin. Recombinant human Hsp90 α, fused to His-tag at N-terminus, was cloned into an E. coli expression vector and was purified to apparent homogeneity by using conventional column chromatography techniques.