Description_x000D_ Biochem/physiol Actions_x000D_ Geldanamycin-Biotin is a benzoquinone ansamycin antitumor antibiotic. Geldanamycin binds specifically to Hsp90 (HeatShock Protein 90). and to its endoplasmic reticulum homologue GP96. The Hsp90 chaperone is required for the activation of several families of eukaryotic protein kinases and nuclear hormone receptors, many of which are proto-oncogenic and play a prominent role in cancer. The geldanamycin antibiotic has antiproliferative and antitumor effects, as it binds to Hsp90, inhibits the HSP90-mediated conformational maturation/refolding reaction, and results in the degradation of Hsp90 substrates. Hsp90 also plays a key role in regulating the physiology of cells exposed to environmental stress and thus, geldanamycin interferes with cellular stess response._x000D_ Geldanamycin-Biotin is a cell permeable HSP90 inhibitor._x000D_ Geldanamycin was isolated from Streptomyces hygroscopicus in 1970 and is highly hepatotoxic. It helps to decrease the acute respiratory distress syndrome and induces the survival of mice affected with virulent H5N1 influenza virus. Geldanamycin also blocks the chaperone actions of the Hsp90 protein._x000D_ Other Notes_x000D_ It is recommended that the product be stored desiccated and protected form light at at −20 °C. Geldanamycin-Biotin as supplied is stable for 5 years when stored properly. Solutions is DMSO are stable for at least two weeks when stored at −20 °C. Geldanamycin decomposes in acidic solution.