Heat shock factor 1 (HSF1) is a major transactivator of heat shock proteins in response to environmental changes, and it is also involved in oogenesis, spermatogenesis, and placental development. Best known for its involvement in heat shock response, Hsf1p regulates the transcription of hundreds of targets, including genes involved in protein folding, detoxification, energy generation, carbohydrate metabolism, and cell wall organization. Recombinant HSF1, fused to His tag, was expressed in E.coli and purified by using conventional chromatography techniques.