Geldanamycin, 1 mg

From STEMCELL Technologies, this small molecule is a benzoquinone ansamycin antibiotic (chemical formula C₂₉H₄₀N₂O₉; CAS 30562-34-6) that selectively inhibits heat shock protein 90 (Hsp90). It binds with high affinity to the N-terminal ATP-binding site of Hsp90, with a reported Kd of 1.2 µM (Roe et al.), and also interacts with the endoplasmic reticulum chaperone GRP94. Binding to GRP94 destabilises its complex with p185-ERBB2, leading to degradation of ERBB2 protein, which is overexpressed in aggressive breast cancers (Castagnola et al.; Chavany et al.).

The compound has a molecular weight of 560.6 g/mol and a reported purity of ≥ 98%. It is supplied as a crystalline solid and is stable for 12 months from date of receipt when stored at -20°C and protected from prolonged exposure to light. For long-term storage, it should be stored with a desiccant. Solubility in DMSO is reported at ≤ 15 mM; the compound has low solubility in aqueous media. For cell culture use, stock solutions should be diluted into culture medium immediately before use, avoiding final DMSO concentrations above 0.1% due to potential cell toxicity.

Published applications include inhibition of growth in 60 human tumor cell lines (Supko et al.), regulation of innate immune response through inhibition of inflammasome activity in a mouse gout model (Mayor et al.), and inhibition of herpes simplex virus type 1 and type 2 replication (Li et al.).