The2-AAlabelingkitcontainstwosetsofthefollowingreagents(15samplesperkit)suppliedinglassampoulessealedunderpurenitrogen: 2-aminobenzoicacid(2-AAdye) Dimethylsulfoxide(DMSO) Aceticacid Sodiumcyanoborohydrideor2-picolineborane
TrADItional2-ABand2-AAlabellingkitsusesodiumcyanoborohydrideasareducingagentduringglycanlabeling.Thisreagentistoxicsoafumecupboardshouldbeusedduringhandling.ToconformwithemerginghealthandsafetyregulationswearenowreplacingthesewithournewVPglycankitsthatusepicolineboranewhichisasignificantlysaferreductant.
NumberofSamplesOne2-AAlabelingkitcontainsreagentstolabelupto30separateanalyticalsamplesperkit.
Dyepurity>99%byHPLC
Molecularweight137
LamBDa-ex320nm
Lambda-em420nm
AmountofSampleFrom25pmolupto25nmolglycanspersample.
SuitableSamplesAnypurifiedglycanswithfreereducingterminicanbelabeled.
StructuralIntegrityNodetectable(<2molepercent)lossofsialicacid,fucose,sulfate,orphosphate.
LabelingEfficiencyTypically>85%(dependentonsample).
LabelingSelectivityEssentiallystoichiometriclabeling.
Protocol1. PurifytheglycansLudgerCleanEB10cartidges(LC-EB10-A6)havebeendesignedforpurificationofglycansfromproteins,salts,anddetergents.
2.TransfersampletoreactionvialTheamountofsampleshouldbeintherange100picomoles–50nanomolesforaglycanpoolobtainedfromatypicalglycoprotein.Withasinglepureglycanaslittleas5picomolescanbelabeledanddetectedinsubsequentHPLCanalysis.SuitablereactionvialsincludesmallpolypropylenemicrocentrifugetubesandtubesforPCRwork.
3. DrythesamplesIdeally,samplesshouldbedriedusingacentrifugalevaporator.IfthisisnotpossIBLethenfreezedrying(lyophilization)canbeusedwithcaution(inparticular,ensurethatthesampledriestoasmall,compactmassattheverybottomofthevial).Donotsubjectsamplestohightemperatures(>28°C)orextremesofpHastheseconditionswillresultinacidcatalysedlossofsialicacids(hightemperatures,lowpH)orepimerizationoftheglycanreducingterminus(athighpH).
4.PrepareaDMSO-aceticacidmixtureAdd150μLglacialaceticacidtothevialofDMSOandmixbyPipetteaction.
5.AddthedyeAdd100μLoftheDMSO-aceticacidmixturetoavialofthe2-AA(2-aminobenzoicacid)dyeandmixuntilthedyeisdissolved.
6.AddthereductantAddthedissolveddyetoavialofsodiumcyanoborohydrideorpicolineboraneandmixbypipetteactionuntilthereductantiscompletelydissolvedtomakethefinallabelingreagent.
7.Add2-AAlabelingreagenttosamplesAdd5μLoflabelingreagenttoeachdriedglycansample,capthemicrotube,mixthoroughly.
8.IncubatePlacethereactionvialsinaheatingblock,sandtray,ordryovensetat65°Candincubatefor3hours.Inmostcases,theincubationtimecanbeshortenedto2hoursorextendedupto4hourswithoutsignificantlychangingtheoutcomeofthelabelingreaction.
9.CentrifugeandcoolAftertheincubationperiodremovethesamples,centrifugethemicrotubesbriefly,thenallowthemtocoolcompletelytoroomtemperature.
10.SampleCleanupPost-labelingsamplecleanupisrecommendedtoremoveexcessdyeandotherlabelingreagents.CleanupcanbeachievedusingLudgerCleanT1cartridges(LC-T1-A6)orScartridges(LC-S-A6)
2-AALabelingReferences
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Anumula,KR;Dhume,STHighresolutionandhighsensitivitymethodsforoligosaccharidemappingandcharacterizationbynormalphasehighperformanceliquidchromatographyfollowingderivatizationwithhighlyfluorescentanthranilicacid.GlycoBIOLOGy8:685-694(1998)
Anumula,KR;Du,PCharacterizationofcarbohydratesusinghighlyfluorescent2-aminobenzoicacidtagfollowinggelelectrophoresisofglycoproteins.AnalyticalBiochemistry275:236-242(1999)
Bigge,JC;Patel,TP;Bruce,JA;Goulding,PN;Charles,SM;Parekh,RBNonselectiveandefficientfluorescentlabelingofglycansusing2-aminobenzamideandanthranilicacid.AnalyticalBiochemistry230:229-238(1995)
Frears,ER;Merry,AH;Axford,JSScreeningneutralandacidicIgGN-glycansbyhighdensityelectrophoresis.GlycoconjugateJournal16:283-290(1999)
Huang,Z;Prickett,T;Potts,M;Helm,RFTheuseofthe2-aminobenzoicacidtagforoligosaccharidegelelectrophoresis.CarbohydrateResearch328:77-83(2000)
Sato,K;Sato,K;Okubo,A;Yamazaki,SDeterminationofmonosaccharidesderivatizedwith2-aminobenzoicacidbycapillaryelectrophoresis.strong>AnalyticalBiochemistry251:119-121(1997)