LC Labs/L6100 Leptomycin B, Free Acid, >98%/L6100/1 mg

Morethan1,000labsworldwidehavepurchasedLeptomycinBfromLCLabs(eitherdirectlyfromusorfromourmanydistributors,manyofwhomresellundertheirownlabels).
LeptomycinB(LepB)isapotent,specificinhibitorofnuclearexportsignal(NES)-dependentproteinexportfromthenucleus.Fukuda.M.,etal."CRM1isresponsibleforintracellulartransportmediatedbythenuclearexportsignal."Nature390:308-311(1997).
TheeffectofLepBontheCRM1(exportin1)NESreceptorresultsfromselectivealkylationbyLepBofasinglecysteineresidue.Kudo,N.,etal."LeptomycinBinactivatesCRM1/exportin1bycovalentmodificationatacysteineresidueinthecentralconservedregion."Proc.Natl.Acad.Sci.USA96:9112-9117(1999)
LepBinhibitsthenucleo-cytoplasmictranslocationoftheHIVRevproteinatnanomolarconcentrations.Wolff,B.,etal."LeptomycinBisaninhibitorofnuclearexport:inhibitionofnucleo-cytoplasmictranslocationofthehumanimmunodeficiencyvirustype1(HIV-1)RevproteinandRev-dependentmRNA."ChemBiol.4:139-147(1997).
LepBalsoexhibitspotentantitumoractivityinvitroandinvivo,andpossessespotentantimycoticandantibioticactivity.Tunac,J.B.,etal."Novelantitumorantibiotics,CI-940(PD114,720)andPD114,721.Taxonomy,fermentationandbiologicalactivity."J.Antibiot.38:460-465(1985).
POTENCY:LepBtypicallyexhibitsIC50valuesinthe1nMrange,dependingonthespecies,celltype,andphenomenonunderstudy.
OurLepBissuppliedinserumbottleswithteflon-linedclosurescontainingasolutioninabsoluteethanol(abettersolventthanmethanol/water;see"Solvent"below).
- The100µgsizeissuppliedas185µLofa1mMsolution(540µg/mL).
- The500µgsizeissuppliedas925µLofa1mMsolution.
- The1mgsizeissuppliedas1.85mLofa1mMsolution.
- Largerquantitiesandhigherconcentrationsareavailable-pleaserequestaquotation.
- SOLVENT:WARNING--LEPTOMYCINBISUNSTABLEINDMSO.DONOTUSEANYDMSOWITHLEPTOMYCINB.EthanolisabettersolventforLepBthanmethanolforatleastthreereasons.First,publishedinformationindicatesthatLepBismorestableinethanol(purityunchangedafter5monthsatroomtemperature:USpatent4,771,070)thaninmethanol/water70/30(freezertemperaturesrequiredforstorageformorethanafewdays:SigmanewsletterLifeScience2,April2001,page11).Second,ethanolhasasignificantlyhigherboilingpointthanmethanol,soethanolsolutionsareexpectedtobelesssusceptibletochangesinconcentrationduetosolventevaporation.Third,LepBisarelativelyhydrophobiccompound,andmayhaveatendencytosticktoplastic.Beingamuchstrongerorganicsolventthanmethanol/water,ethanolreducesthepotentiallossofLepBwhenhandledinplastic.
- DILUTINGLepBSOLUTIONS:DilutionsofLepBfordoseresponsestudiesshouldbemadeinanorganicsolvent,preferablyethanol,withonlythefinaldilutionbeingmadeintoculturemedium.
- STABILITYWARNING:LepBinanyquantityisunstablewhendrieddownintoafilm.Thus,undernocircumstancesshouldthesolventberemovedfromsolutionsofLepB,becauserapiddecompositionandlossofrecoverablematerialwillresult.
- Wenotethat,asofAugust2010,atleastthreesuppliers,namelySelleckChemicalsLLC,Biotrend,nowsellleptomycinBinadried-down,solvent-freeform.FromourexperienceitishighlylikelythatthesolidformwillprovidefarlessthantheamountsofleptomycinBclaimedonthesevendorsviallabels.TheoriginalreportdescribingleptomycinBstatedquiteclearlythatleptomycinBisunstableasasolidandcannotbedrieddownandthensuccessfullyusedatitsexpectedpotency.Forexample,wetestedasampleofdried-downleptomycinBfromadifferentvendorbytreatingitwithmethanol,anexcellentleptomycinBsolvent,andthendoinganHPLCassay.Theresultwasanice,clean-lookingpeakthatshowedhighpurity.HOWEVER,THISISVERYMISLEADING--ITWASANICECLEANPEAK,BUTWHENCAREFULLYQUANTITATED,ITCONTAINEDLESSTHAN40%OFTHEEXPECTEDAMOUNTOFLEPTOMYCINB.ThisindicatesthatdryingleptomycinBdowntoasolidprobablyresultsinpartialpolymerizationtoahighlyinsolublematerialthatcannotberedissolved.So,wepredictthatuseofleptomycinBindried-solidformfromanysourcewillresultinlargeamountsofwastedtimeandmoney.
- STABILITYTESTING:TotestLepBstabilityinethanol,wetestedLepBdilutionsundertwodifferenttemperatureconditions.Onesetofsampleswasmaintainedatfreezertemperaturesafterpurificationanddilution,andthensentinicetoanacademiclaboratoryinTexas.Asecondsetofsampleswasheatedinanovento60ºCfortwohours,thenshippedtothesameTexaslab,inthemiddleofAugust,withouticeorrefrigeration,andthesampleswereassayedforinhibitionofCOScellgrowth.Nosignificantdifferenceswerefoundbetweenthetwotemperatureconditions.Inanothertest,werefluxedasampleofourLepBinethanol(b.p.78.5ºC)foranhour;attheendofthisperiod,HPLCanalysisshowedthatdecompositionproductsamountedtolessthan2%.
- SHIPPINGCONDITIONS:WeshipourLepBproductatambienttemperature,withoutice.AlltheinformationwehaveindicatesthatLepBisstableforatleastmanydays,ifnotmonths,underambientconditions.Thus,theextracostoficeshipmentsdoesnotappeartobejustified.However,formaximumlong-termstability,LepBsolutionsshouldbestoredat-20ºCorcolder.
- Soldforlaboratoryormanufacturingpurposesonly;notforhuman,medical,veterinary,food,orhouseholduse.
RelatedTerms:
[LMB][Elactocin][Mantuamycin][CI-940][CL-1957A][PD-114720][ATS1287B]
M.W.540.73
C33H48O6
[87081-35-4]
M.I.14:5444
Storage
Storetightlysealedatorbelow-20ºC
Solubility
Solubleinmethanolorethanol
Disposal
A

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LC Labs/L6100 Leptomycin B, Free Acid, >98%/L6100/1 mg

RelatedTerms:

Storage

Solubility

Disposal