This affinity purified antibody has been tested for use in ELISA, immunohistochemistry and western blot. This antibody reacts strongly with the acetylated form of the immunizing peptide and shows minimal reactivity with the non-acetylated form when tested by ELISA. To date, western blotting shows equivalent staining of lysates either treated or untreated with Trichostatin A (an HDAC inhibitor). Therefore, western blotting results are not definitive for demonstrating the specificity of this reagent. Specific conditions for reactivity should be optimized by the end user. Expect a band approximately 90 kDa in size corresponding to Hsp90 protein by western blotting in the appropriate cell lysate or extract.