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GENTAUR
Tel: +32 16 58 90 45
Fax: + 32 16 50 90 45
info@genprice.com
Av. de l'Armée 68
• B-1040 BRUSSELS • BELGIUM
GENTAUR FRANCE
Tel: 01 43 25 01 50
9, Rue Lagrange
• 75005 PARIS • FRANCE
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L-6100 Leptomycin B, >99%
Minimum 99% Purity; Solution in Absolute Ethanol
[LMB] [Elactocin] [CI-940] [CL-1957A]
[NSC-364372] [PD-114720]
| M.W. 540.74 |
C33H48O6
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[87081-35-4] |
Storage: Store tightly sealed at or below -20 ºC in the
dark. Solubility: Soluble in methanol or ethanol. Disposal:
A
 | 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 5 µg size is supplied as 185 µL of a 50 µM solution (27 µg/mL). |
| The 10 µg size is supplied as 185 µL of a 100 µM solution (54
µg/mL). |
| The 50 µg size is supplied as 185 µL of a 500 µM solution (270
µg/mL). |
| The 100 µg size is supplied as 185 µL of a 1 mM solution (540
µg/mL). |
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| SOLVENT: 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. NOTE: LepB is also reported to be
unstable in DMSO, so the latter solvent should not be used for dilutions. |
| 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. |
| STABILITY WARNING: Small quantities of LepB are reported to be
unstable when dried down into a film. Thus, under no circumstances should
the solvent be removed from solutions of LepB, because rapid decomposition
may result. |
| STABILITY TESTING: To test LepB stability in ethanol, we tested LepB
dilutions under two different temperature conditions. One set of samples
was maintained at freezer temperatures after purification and dilution, and
then sent in ice to an academic laboratory in Texas. A second set of
samples was heated in an oven to 60 ºC for two hours, then shipped to the
same Texas lab, in the middle of August, without ice or refrigeration,
and the samples were assayed for inhibition of COS cell growth. No
significant differences were found between the two temperature conditions.
In another test, we refluxed a sample of our LepB in ethanol (b.p. 78.5 ºC)
for an hour; at the end of this period, HPLC analysis showed that
decomposition products amounted to less than 1%. |
| SHIPPING CONDITIONS: We ship our LepB product at ambient temperature,
without ice. All the information we have indicates that LepB is stable for
at least many days, if not months, under ambient conditions. Thus, the
extra cost of ice shipments does not appear to be justified. However, for
maximum long-term stability, LepB solutions should be stored at -20 ºC or
colder. |
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