產(chǎn)品名稱：Leptomycin B, Free Acid 產(chǎn)品貨號：LC L-6100 產(chǎn)品規(guī)格：1 MG Leptomycin B (LepB) is a potent, specific inhibitor of nuclear export signal (NES)-dependent protein export from the nucleus. Fukuda. M., et al. "CRM1 is responsible for intracellular transport mediated by the nuclear export signal." Nature 390: 308-311 (1997). The effect of LepB on the CRM1 (exportin 1) NES receptor results from selective alkylation by LepB of a single cysteine residue. Kudo, N., et al. "Leptomycin B inactivates CRM1/exportin 1 by covalent modification at a cysteine residue in the central conserved region." Proc. Natl. Acad. Sci. USA 96: 9112-9117 (1999). LepB inhibits the nucleo-cytoplasmic translocation of the HIV Rev protein at nanomolar concentrations. Wolff, B., et al. "Leptomycin B is an inhibitor of nuclear export: inhibition of nucleo-cytoplasmic translocation of the human immunodeficiency virus type 1 (HIV-1) Rev protein and Rev-dependent mRNA." Chem Biol. 4: 139-147 (1997). LepB also exhibits potent antitumor activity in vitro and in vivo, and possesses potent antimycotic and antibiotic activity. Tunac, J.B., et al. "Novel antitumor antibiotics, CI-940 (PD 114,720) and PD 114,721. Taxonomy, fermentation and biological activity." J. Antibiot. 38: 460-465 (1985). POTENCY: LepB typically exhibits IC50 values in the 1 nM range, depending on the species, cell type, and phenomenon under study. Our LepB is supplied in serum bottles with teflon-lined closures containing a solution in absolute ethanol (a better solvent than methanol/water; see "Solvent" below). The 100 µg size is supplied as 185 µL of a 1 mM solution (540 µg/mL). The 500 µg size is supplied as 925 µL of a 1 mM solution. The 1 mg size is supplied as 1.85 mL of a 1 mM solution. Larger quantities and higher concentrations are available - please request a quotation. SOLVENT: WARNING -- LEPTOMYCIN B IS UNSTABLE IN DMSO. DO NOT USE ANY DMSO WITH LEPTOMYCIN B. Ethanol is a better solvent for LepB than methanol for at least three reasons. First, published information indicates that LepB is more stable in ethanol (purity unchanged after 5 months at room temperature: US patent 4,771,070) than in methanol/water 70/30 (freezer temperatures required for storage for more than a few days: Sigma newsletter LifeScience 2, April 2001, page 11). Second, ethanol has a significantly higher boiling point than methanol, so ethanol solutions are expected to be less susceptible to changes in concentration due to solvent evaporation. Third, LepB is a relatively hydrophobic compound, and may have a tendency to stick to plastic. Being a much stronger organic solvent than methanol/water, ethanol reduces the potential loss of LepB when handled in plastic. DILUTING LepB SOLUTIONS: Dilutions of LepB for dose response studies should be made in an organic solvent, preferably ethanol, with only the final dilution being made into culture medium. Storage: Store tightly sealed at or below -20 ºC. Solubility: Soluble in methanol or ethanol. Disposal: A
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