Megazyme/Lichenan（冰岛苔藓）/P-LICHN/4克
商品编号：
P-LICHN
品牌：
Megazyme INC
市场价：
¥3288.00
美元价：
1972.80
产品分类：
其他试剂
公司分类：
Other_reagents
联系Q Q：
3392242852
电话号码：
4000-520-616
电子邮箱：
info@ebiomall.com
商品介绍
HighpurityLichenan(IcelandicMoss)foruseinresearch,biochemicalenzymeassaysandinvitrodiagnosticanalysis.
Purity~80%.1,3:1,4-β-D-Glucan.Glucose1.5%.Contaminantisnotstarchorphytoglycogen,itappearstobeisolichenan.
RT-CaCCOprocess:animprovedCaCCOprocessforricestrawbyitsincorporationwithastepoflimepretreatmentatroomtemperature.
Shiroma,R.,Park,J.Y.,Al-Haq,M.I.,Arakane,M.,Ike,M.&Tokuyasu,K.(2011).BioresourceTechnology,102(3),2943-2949.
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WeimprovedtheCaCCOprocessforricestrawbyitsincorporationwithastepoflimepretreatmentatroomtemperature(RT).WefirstlyoptimizedtheRT-limepretreatmentforthelignocellulosicpart.Whentheratiooflime/dry-biomasswas0.2(w/w),theRTlime-pretreatmentfor7-dresultedinaneffectontheenzymaticsaccharificationofcelluloseandxylanequivalenttothatofthepretreatmentat120°Cfor1h.Sucrose,starchandβ-1,3-1,4-glucan,whichcouldbeoftendetectedinricestraw,weremostlystableundertheRT-limepretreatmentcondition.Then,thepretreatmentconditionintheconventionalCaCCOprocesswasmodifiedbytheadaptationoftheoptimizedRTlime-pretreatment,resultinginsignificantlybettercarbohydraterecoveriesviaenzymaticsaccharificationthanthoseoftheCaCCOprocess(120°Cfor1h).Thus,theimprovedCaCCOprocess(theRT-CaCCOprocess)couldpreserve/pretreatthefeedstockatRTinawetformwithminimumlossofcarbohydrates.
Real-timeimagingofcellulosereorientationduringcellwallexpansioninArABIdopsisroots.
Anderson,C.T.,Carroll,A.,Akhmetova,L.&Somerville,C.(2010).PlantPhysiology,152(2),787-796.
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Celluloseformsthemajorload-bearingnetworkoftheplantcellwall,whichsimultaneouslyprotectsthecellanddirectsitsgrowth.Althoughtheprocessofcellulosesynthesishasbeenobserved,littleisknownaboutthebehaviorofcelluloseinthewallaftersynthesis.UsingPontamineFastScarlet4B,adyethatfluorescespreferentiallyinthepresenceofcelluloseandhasexcitationandemissionwavelengthssuitableforconfocalmicroscopy,weimagedthearchitectureanddynamicsofcelluloseinthecellwallsofexpandingrootcells.WefoundthatcelluloseexistsinArabidopsis(Arabidopsisthaliana)cellwallsinlargefibrillarbundlesthatvaryinorientation.Duringanisotropicwallexpansioninwild-typeplants,weobservedthatthesecellulosebundlesrotateinatransversetolongitudinaldirection.Wealsofoundthatcelluloseorganizationissignificantlyalteredinmutantslackingeitheracellulosesynthasesubunitortwoxyloglucanxylosyltransferaseisoforms.Ourresultssupportamodelinwhichcelluloseisdepositedtransverselytoaccommodatelongitudinalcellexpansionandreorientedduringexpansiontogenerateacellwallthatisfortifiedagainststrainfromanydirection.
Characterizationandthree-dimensionalstructuresoftwodistinctbacterialxyloglucanasesfromfamiliesGH5andGH12.
Gloster,T.M.,Ibatullin,F.M.,Macauley,K.,Eklöf,J.M.,Roberts,S.,Turkenburg,J.P.,Bjørnvad,M.E.,Jørgensen,P.L.,Danielsen,S.,Johansen,K.S.,Borchert,T.V.,Wilson,K.S.,Brumer,H.&Davies,G.J.(2007).JournalofBIOLOGicalChemistry,282(26),19177-19189.
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Theplantcellwallisacomplexmaterialinwhichthecellulosemicrofibrilsareembeddedwithinameshofotherpolysaccharides,someofwhicharelooselytermed“hemicellulose.”Onesuchhemicelluloseisxyloglucan,whichdisplaysaβ-1,4-linkedD-glucosebackbonesubstitutedwithxylose,galactose,andoccasionallyfucosemoieties.BothxyloglucanandtheenzymesresponsIBLeforitsmodificationanddegradationarefindingincreasingprominence,reflectingboththedriveforenzymaticbiomassconversion,theirroleindetergentapplications,andtheutilityofmodifiedxyloglucansforcellulosefibermodification.Herewepresenttheenzymaticcharacterizationandthree-dimensionalstructuresinligand-freeandxyloglucan-oligosaccharidecomplexedformsoftwodistinctxyloglucanasesfromglycosidehydrolasefamiliesGH5andGH12.Theenzymes,PaenibacilluspabuliXG5andBacilluslicheniformisXG12,bothdisplayopenactivecentergroovesgraftedupontheirrespective(β/α)8andβ-jellyrollfolds,inwhichthesidechaindecorationsofxyloglucanmaybeaccommodated.Fortheβ-jellyrollenzymetopologyofGH12,bindingofxylosylandpendantgalactosylmoietiesistolerated,buttheenzymeissimilarlycompetentinthedegradationofunbranchedglucans.Inthecaseofthe(β/α)8GH5enzyme,kineticallyproductiveinteractionsaremadewithbothxyloseandgalactosesubstituents,asreflectedinbothahighspecificactivityonxyloglucanandthekineticsofaseriesofarylglycosides.Thedifferentialstrategiesfortheaccommodationofthesidechainsofxyloglucanpresumablyfacilitatetheactionofthesemicrobialhydrolasesinmilieuswherediverseanddifferentlysubstitutedsubstratesmaybeencountered.
Novelxylan-bindingpropertiesofanengineeredfamily4carbohydrate-bindingmodule.
Gunnarsson,L.C.,Montanier,C.,Tunnicliffe,R.B.,Williamson,M.P.,Gilbert,H.J.,Nordberg,K.E.&Ohlin,M.(2007).Biochem.J,406(2),209-214.
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Molecularengineeringofligand-bindingproteinsiscommonlyusedforidentificationofvariantsthatdisplaynovelspecificities.UsingthisapproachtointroducenovelspecificitiesintoCBMs(carbohydrate-bindingmodules)hasnotbeenextensivelyexplored.Here,wereporttheengineeringofaCBM,CBM4-2fromtheRhodothermusmarinusxylanaseXyn10A,andtheidentificationoftheX-2variant.Ascomparedwiththewild-typeprotein,thisengineeredmoduledisplayshigherspecificityforthepolysaccharidexylan,andalowerpreferenceforbindingxylo-oligomersratherthanbindingthenaturaldecoratedpolysaccharide.ThemodeofbindingofX-2differsfromotherxylan-specificCBMsinthatitonlyhasonearomaticresidueinthebindingsitethatcanmakehydrophobicinteractionswiththesugarringsoftheligand.TheevolutionofCBM4-2hasthusgeneratedaxylan-bindingmodulewithdifferentbindingpropertiestothosedisplayedbyCBMsavailableinNature.
RecombinantexpressionandenzymaticcharacterizationofPttCel9A,aKORhomologuefromPopulustremulaxtremuloides.
Master,E.R.,Rudsander,U.J.,Zhou,W.,Henriksson,H.,Divne,C.,Denman,S.,WilsonD.B.&Teeri,T.T.(2004).Biochemistry,43(31),10080-10089.
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PttCel9Aisamembrane-bound,family9glycosylhydrolasefromPopulustremulaxtremuloidesthatisupregulatedduringsecondarycellwallsynthesis.ThecatalyticdomainofPttCel9A,Δ1-105PttCel9A,waspurified,anditsactivitywascomparedtoTfCel9AandTfCel9BfromThermobifidafusca.Sincearomaticaminoacidsinvolvedinsubstratebindingatsubsites−4,−3,and−2aremissinginPttCel9A,theactivityofTfCel9AmutantenzymesW256S,W209A,andW313Gwasalsoinvestigated.Δ1-105PttCel9Ahydrolyzedacomparativelynarrowrangeofpolymericsubstrates,andthepreferredsubstratewas(carboxymethyl)cellulose4M.Moreover,Δ1-105PttCel9Adidnothydrolyzeoligosaccharidesshorterthancellopentaose,whereasTfCel9AandTfCel9Bhydrolyzedcellotetraoseandcellotriose,respectively.ThesedatasuggestthatthepreferredsubstratesofPttCel9Aarelong,low-substituted,solublecellulosicpolymers.At30°CandpH6.0,thekcatforcellohexaoseofΔ1-105PttCel9A,TfCel9A,andTfCel9Bwere0.023±0.001,16.9±2.0,and1.3±0.2,respectively.Thecatalyticefficiency(kcat/km)ofTfCel9Bwas39%ofthatofTfCel9A,whereasthecatalyticefficiencyofΔ1-105PttCel9Awas0.04%ofthatofTfCel9A.Removingtryptophanresiduesatsubsites−4,−3,and−2decreasedtheefficiencyofcellohexaosehydrolysisbyTfCel9A.MutationofW313toGhadthemostdrasticeffect,producingamutantenzymewith1%ofthecatalyticefficiencyofTfCel9A.TheapparentnarrowsubstraterangeandcatalyticefficiencyofPttCel9Aarecorrelatedwithalackofaromaticaminoacidsinthesubstratebindingcleftandmaybenecessarytopreventexcessivehydrolysisofcellwallpolysaccharidesduringcellwallformation.
Neoglycolipid-Based“Designer”OligosaccharideMicroarraystoDefineβ-GlucanLigandsforDectin-1.
Palma,A.S.,Zhang,Y.,Childs,R.A.,Campanero-Rhodes,M.A.,Liu,Y.,Feizi,T.&Chai,W.(2012).CarbohydrateMicroarrays,808(2),337-359.
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Inthischapter,wedescribethekeystepsofthe“designer”oligosaccharidemicroarrayapproachwefollowedtoprovethecarbohydratebindingactivityanddefinetheoligosaccharideligandsforDectin-1,anatypicalC-typelectin-likesignalingreceptorofthemammalianinnateimmunesystemwithakeyroleinanti-fungalimmunity.Theterm“designer”microarray,whichweintroducedinthecourseoftheDectin-1studyreferstoamicroarrayofoligosaccharideprobesgeneratedfromligand-bearingglycoconjugatestorevealtheoligosaccharideligandstheyharbor,sothatthesecanbeisolatedandcharacterized.Oligosaccharideprobesweregeneratedfromtwopolysaccharides,onethatwasboundbyDectin-1andknowntoberichinβ1,3-glucosesequenceandanotherthatwasnotboundandwasrichinβ1,6-glucosesequenceandservedasanegativecontrol.Theapproachinvolved:classicELISA-typebindingassaystoselectthepolysaccharides;partialdepolymerizationofthepolysaccharidesbychemicalhydrolysis;fractionationbysizeoftheglucanoligosaccharidesobtainedanddeterminationoftheirchainlengthsbymassspectrometry;detectionofDectin-1ligand-positiveandligand-negativeoligosaccharidesusingtheneoglycolipid(NGL)technology;methylationanalysisofoligosaccharidestoderiveglucoselinkageinformation,andincorporationofthenewlygeneratedglucanoligosaccharideprobesintomicroarraysencompassingdiversemammalian-typeandexogenoussequencesformicroarrayanalysisofDectin-1.
CloningofanendoglycanasegenefromPaenibacilluscookiiandcharacterizationoftherecombinantenzyme.
Shinoda,S.,Kanamasa,S.&Arai,M.(2012).BiotechnologyLetters,34(2),281-286.
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AnendoglycanasegeneofPaenibacilluscookiiSS-24wasclonedandsequenced.ThisPgl8AgenehadanopenreADIngframeof1,230bpthatencodedaputativesignalsequence(31aminoacids)andmatureenzyme(378aminoacids:41,835Da).Theenzymewasmosthomologoustoaβ-1,3-1,4-glucanaseofBacilluscirculansWL-12with84%identity.Therecombinantenzymehydrolyzedcarboxymethylcellulose,swollencelluloses,chitosanandlichenanbutnotAvicel,chitinpowderorxylan.Withchitosanasthesubstrate,theoptimumtemperatureandhydrolysisproductsoftherecombinantenzymevariedatpH4.0and8.0.ThisisthefirstreportthatcharacterizeschitosanaseactivityunderdifferentpHconditions.
Structuralevidencefortheevolutionofxyloglucanaseactivityfromxyloglucanendo-transglycosylases:biologicalimplicationsforcellwallmetabolism.
Baumann,M.J.,Eklöf,J.M.,Michel,G.,Kallas,Å.M.,Teeri,T.T.,Czjzek,M.&Brumer,H.(2007).ThePlantCell,19(6),1947-1963.
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High-resolution,three-dimensionalstructuresofthearchetypalglycosidehydrolasefamily16(GH16)endo-xyloglucanasesTm-NXG1andTm-NXG2fromnasturtium(Tropaeolummajus)havebeensolvedbyx-raycrystallography.KeystructuralfeaturesthatmodulatetherelativeratesofsubstratehydrolysistotransglycosylationintheGH16xyloglucan-activeenzymeswereidentifiedbystructure–functionstudiesoftherecombinantlyexpressedenzymesincomparisonwithdataforthestrictxyloglucanendo-transglycosylasePtt-XET16-34fromhybridaspen(Populustremula×Populustremuloides).ProductionoftheloopdeletionvariantTm-NXG1-ΔYNIIGyieldedanenzymethatwasstructurallysimilartoPtt-XET16-34andhadagreatlyincreasedtransglycosylation:hydrolysisratio.ComprehensivebioinformaticanalysesofXTHgeneproducts,togetherwithdetailedkineticdata,stronglysuggestthatxyloglucanaseactivityhasevolvedasagainoffunctioninanancestralGH16XETtomeetspecificbiologicalrequirementsduringseedgermination,fruitripening,andrapidwallexpansion.
Acomparativestudyonstructure–functionrelationsofmixed-linkage(1→3),(1→4)linearβ-D-glucans.
Lazaridou,A.,Biliaderis,C.G.,Micha-Screttas,M.&Steele,B.R.(2004).FoodHydrocolloids,18(5),837-855.
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Theeffectsoffinestructureandmolecularsizeontherheologicalpropertiesofsixmixed-linkage(1→3),(1→4)-β-D-glucans(β-glucans)inthesolutionandgelstatewerestudied.Molecularsizecharacterizationwascarriedoutwithhigh-performancesizeexclusionchromatographycombinedwitharefractiveindexdetector.Samplesweredividedintotwogroupsaccordingtothevaluesofapparentmolecularweight(Mw)ofthepeakfractionofthemainelutingpeakcalculatedas200×103foranoat,abarley,andawheatβ-glucanand∼100×103foranoatandabarleyβ-glucan,andalichenansample.Allpolysaccharidesanalyzedby2DNMRspectroscopyandhigh-performanceanion-exchangechromatographyofthecellulosicoligomersreleasedbytheactionoflichenaseshowedthetypicalfinestructureofmixed-linkagelinear(1→3),(1→4)-β-D-glucan.Followinglichenasedigestionofβ-glucans,themolarratiosoftri-totetrasaccharides(DP3/DP4)werefoundtofollowtheorderoflichenan(24.5)>wheat(3.7)>barley(2.8–3.0)>oat(2.1).Differencesincriticalconcentration(c**),viscosity,viscoelasticandshearthinningpropertiesamongsamplesweredependentmainlyondifferencesinmolecularsizeofthepolymericchainsaswellasontheβ-glucanfinestructure.Allβ-glucanisolateswereabletoformgels,asprobedbydynamicrheometry;withdecreasingmolecularsizeandincreasingDP3/DP4ratio,thegelationtimedecreasedandthegelationrate(IE=[dlogG"/dt]max)increased.Differentialscanningcalorimetry(DSC)showedthatcerealβ-glucangelsexhibitratherbroadendothermicgel→soltransitionsat55–80°C,whilelichenangelsgiveasharpertransition,implyingamorecooperativeprocess.TheDSCkineticdatashowedsimilarresponsestothatfromdynamicrheometry;therateofdevelopmentoftheendothermincreasedwithincreasingDP3/DP4ratioofthepolysaccharide.Furthermore,thestoragemodulus(G′)andtheapparentmeltingenthalpyvalues(plateauΔH)increasedwithdecreasingmolecularsizeandwithincreasingDP3/DP4ratio.Themeltingtemperatureofthegelnetwork,asdeterminedbyDSCanddynamicrheometry,wasfoundtoincreasewiththemolecularsizeandtheDP3/DP4ratioofβ-glucans;theTmforlichenanwas∼89°Candforcerealβ-glucansvariedinthenarrowrangeof∼65–72°C.Largedeformationmechanicaltests(compressionmode)uptofailurerevealedanincreaseinstrengthandadecreaseinbrittlenessofmixed-linkageβ-glucangelswithincreasingDP3/DP4ratioandmolecularsizeofthepolysaccharide.
Evaluationofstructureintheformationofgelsbystructurallydiverse(1→3)(1→4)-β-D-glucansfromfourcerealandonelichenspecies.
Tosh,S.M.,Brummer,Y.,Wood,P.J.,Wang,Q.&Weisz,J.(2004).CarbohydratePolymers,57(3),249-259.
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The(1→3)(1→4)-β-D-glucansfromfourcerealsources(oats,wheat,barleyandrye)andonelichensource(Icelandicmoss)wereusedtotesttwoproposedstructurallybasedhypothesesaboutthegellingmechanismofthesepolymers.Structureswereevaluatedusinghighperformanceanionexchangechromatographyoftheoligosaccharidefragmentsreleasedbya(1→3)(1→4)-β-D-glucan-4-glucanohydrolase.Thisdeterminedtherelativeamountsofcellodextrinunits,ofdifferentdegreesofpolymerisation,whicharejoinedbyβ-(1→3)linkagesintheintactpolysaccharidechain.Oatβ-glucanhadthelowestβ-(1→3)-linkedcellotriosylunitcontentandlichenanhadthehighest.Strongcorrelationswerefoundbetweenthefractionofβ-(1→3)-linkedcellotriosylunitsintheβ-glucansandtheelasticityof6%gelsinwater,asmeasuredbydynamicrheometry.Differentialscanningcalorimetryshowedthattheβ-(1→3)-linkedcellotriosylunitcontentwasalsocorrelatedwiththeonsetandpeaktemperatureswhen6%β-glucangelsweremelted.Nocorrelationwasfoundbetweenthelonger(DP6–9)β-(1→3)-linkedcellodextrinoligosaccharidecontentandeitherthegelelasticityormeltingcharacteristics.Thesefindingsareconsistentwithamodelinwhichrunsofconsecutiveβ-(1→3)-linkedcellotriosylunitsformthejunctionzonesinthegelnetwork,butnotwithamodelinwhichlongerβ-(1→3)-linkedcellodextrinsassociate,asincellulosefibres,toproducethegelnetwork.Microscopicimagesoftheβ-glucangelsfromthefivespeciesrevealedthatthemicrostructurewasnothomogeneousinanyofthesamples,whichmayberelatedtothevariabilityintheenthalpyofmeltingofgels.Therewasacoarseningofgelstructureastheβ-(1→3)-linkedcellotriosylunitcontentincreased.
Afibrolyticpotentialinthehumanileummucosalmicrobiotarevealedbyfunctionalmetagenomics.
Patrascu,O.,Béguet-Crespel,F.,Marinelli,L.,LeChatelier,E.,Abraham,A.,Leclerc,M.,Klopp,C.,Terrapon,N.,Henrissat,B.,Blottière,H.M.,Doré,J.&ChristelBéra-Maillet.(2017).ScientificReports,7,40248.
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Thedigestionofdietaryfibersisamajorfunctionofthehumanintestinalmicrobiota.Sofarthisfunctionhasbeenattributedtothemicroorganismsinhabitingthecolon,andmanystudieshavefocusedonthisdistalpartofthegastrointestinaltractusingeasilyaccessiblefecalmaterial.However,microbialfermentations,supportedbythepresenceofshort-chainfattyacids,aresUSPectedtooccurintheuppersmallintestine,particularlyintheileum.Usingafosmidlibraryfromthehumanilealmucosa,wescreened20,000clonesfortheiractivitiesagainstcarboxymethylcelluloseandxylanschosenasmodelsofthemajorplantcellwall(PCW)polysaccharidesfromdietaryfibres.ElevenpositiveclonesrevealedabroadrangeofCAZymeencodinggenesfromBacteroidesandClostridialesspecies,aswellasPolysaccharideUtilizationLoci(PULs).Thefunctionalglycosidehydrolasegeneswereidentified,andoligosaccharidebreak-downproductsexaminedfromdifferentpolysaccharidesincludingmixed-linkageβ-glucans.CAZymesandPULswerealsoexaminedfortheirprevalenceinhumangutmicrobiome.Severalclustersofgenesoflowprevalenceinfecalmicrobiomesuggestedtheybelongtounidentifiedstrainsratherspecificallyestablishedupstreamthecolon,intheileum.Thus,theilealmucosa-associatedmicrobiotaencompassestheenzymaticpotentialforPCWpolysaccharidedegradationinthesmallintestine.
Enhancedsaccharificationofreedandricestrawsbytheadditionofβ-1,3-1,4-glucanasewithbroadsubstratespecificityandcalciumion.
Kim,D.U.,Kim,H.J.,Jeong,Y.S.,Na,H.B.,Cha,Y.L.,Koo,B.C.,Kim,J.,Yun,H.D.,Lee,J.K.&Kim,H.(2015).JournaloftheKoreanSocietyforAppliedBiologicalChemistry,58(1),29-33.
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Thepossibilityofusingadditiveenzymestoimprovethesaccharificationoflignocellulosicsubstrateswithcommercialcellulolyticenzymeswasstudied.Reed(Phragmitescommunis)andrice(Oryzasativa)strawpowderswerepretreatedwithNaOH/steamviaahigh-temperatureexplosionsystem.Thesaccharificationofuntreatedreedandricestrawpowdersbycommercialenzymes(Celluclast1.5 L + Novozym188)wasnotsignificantlyincreasedbytheadditionofxylanases(Xyn10J,XynX),acellulase(Cel6H),andaβ-1,3-1,4-glucanase(BGlc8H)withbroadsubstratespecificity.Thesaccharificationofthepretreatedreedandricestrawpowdersbythecommercialenzymeswasincreasedby10.4and4.8 %,respectively,bytheadditionofBGlc8H.InthepresenceofCa2+andBGlc8H,thesaccharificationofthepretreatedreedandricestrawpowdersbythecommercialenzymeswasincreasedby18.5and11.7 %,respectively.NosucheffectofCa2+wasobservedwithXyn10J,XynX,orCel6H.Theresultssuggestthattheenzymaticconversionoflignocellulosicbiomasstoreducingsugarscouldbeenhancedbycertainadditiveenzymessuchasβ-1,3-1,4-glucanase,andthattheenhancementcouldfurtherbeincreasedbyCa2+.
SuberinregulatestheproductionofcellulolyticenzymesinStreptomycesscabiei,thecausalagentofpotatocommonscab.
Padilla-Reynaud,R.,Simao-Beaunoir,A.M.,Lerat,S.,Bernards,M.A.&Beaulieu,C.(2015).Microbesandenvironments,30(3),245-253.
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Suberin,amajorconstituentofthepotatoperiderm,isknowntopromotetheproductionofthaxtomins,thekeyvirulencefactorsofthecommonscab-causingagentStreptomycesscabiei.Inthepresentstudy,wespeculatedthatsuberinaffectedtheproductionofglycosylhydrolases,suchascellulases,byS.scabiei,anddemonstratedthatsuberinpromotedglycosylhydrolaseactivitywhenaddedtocellulose-,xylan-,orlichenin-containingmedia.Furthermore,secretomeanalysesrevealedthattheadditionofsuberintoacellulose-containingmediumincreasedtheproductionofglycosylhydrolases.Forexample,theproductionof13outofthe14cellulasesproducedbyS.scabieiincellulose-containingmediumwasstimulatedbythepresenceofsuberin.Inmostcases,thetranscriptionofthecorrespondingcellulase-encodinggeneswasalsomarkedlyincreasedwhenthebacteriumwasgrowninthepresenceofsuberinandcellulose.Thelevelofasubtilase-likeproteaseinhibitorwasmarkedlydecreasedbythepresenceofsuberin.WeproposedamodelfortheonsetofS.scabieivirulencemechanismsbybothcelluloseandsuberin,themaindegradationproductofcellulosethatactsasaninducerofthaxtominbiosyntheticgenes,andsuberinpromotingthebiosynthesisofsecondarymetabolitesincludingthaxtomins.
Bondsbrokenandformedduringthemixed-linkageglucan:xyloglucanendotransglucosylasereactioncatalysedbyEquisetumhetero-trans-β-glucanase.
Simmons,T.J.&Fry,S.C.(2017).BiochemicalJournal,474(7),1055-1070.
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Mixed-linkageglucan:xyloglucanendotransglucosylase(MXE)isoneofthethreeactivitiesoftherecentlycharacterisedhetero-trans-β-glucanase(HTG),whichamongland-plantsisknownonlyfromEquisetumspecies.ThebiochemicaldetailsoftheMXEreactionwereincompletelyunderstood-detailsthatwouldpromoteunderstandingofMXE"sroleinvivoandenableitsfulltechnologicalexploitation.WeinvestigatedHTG"ssiteofattackononeofitsdonorsubstrates,mixed-linkage(1→3),(1→4)-β-D-glucan(MLG),withradioactiveoligosaccharidesofxyloglucanasacceptorsubstrate.ComparingthreedifferentMLGpreparations,weshowedthattheenzymefavoursthosewithahighcontentofcellotetraoseblocks.Thereactionproductswereanalysedbyenzymicdigestion,thin-layerchromatography,HPLCandgel-permeationchromatography.EquisetumHTGconsistentlycleavedtheMLGatthethirdconsecutiveβ-(1→4)-bondfollowing(towardsthereducingterminus)aβ-(1→3)-bond.Itthenformedaβ-(1→4)-bondbetweentheMLGandthenon-reducingterminalglucoseresidueofthexyloglucanoligosaccharide,consistentwithitsXTHsubfamilymembership.Usingsize-homogeneousbarleyMLGasdonorsubstrate,weshowedthatHTGdoesnotfavouranyparticularregionoftheMLGchainrelativethepolysaccharide"sreducingandnon-reducingtermini;rather,itselectsitstargetcellotetraosylunitstochasticallyalongtheMLGmolecule.Thisworkimprovesourunderstandingofhowenzymescanexhibitpromiscuoussubstratespecificitiesandprovidesthefoundationstoexplorestrategiesforengineeringnovelsubstratespecificitiesintotransglycanases.
CharacterizationofNicotianatabacumplantsexpressinghybridgenesofcyanobacterialδ9orδ12acyl-lipiddesaturasesandthermostablelichenase.
Gerasymenko,I.M.,Sakhno,L.A.,Kyrpa,T.N.,Ostapchuk,A.M.,Hadjiev,T.A.,Goldenkova-Pavlova,I.V.&Sheludko,Y.V.(2015).RussianJournalofPlantPhysiology,62(3),283-291.
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WeestablishedtransgeniclinesofNicotianatabacumexpressinghybridgenesofSynechocystissp.PCC6803Δ12(desA)acyllipiddesaturaseandSynechococcusvulcanusδ9(desC)acyllipiddesaturasewithorwithoutsequencecodingfortransitpeptideofRubiscosmallsubunitofArabidopsisthalianaundercontrolofaconstitutivepromoter.Reliableincreaseoflinoleicacidportion(C18:2;δ9,12)accompaniedwithdecreaseofα-linolenicacid(C18:3;δ9,12,15)relativeamountwasdetectedforplantsexpressinghybriddesA::licBM3gene.Noreliablechangesweredetectedinfattyacidprofilesandunsaturationindexofplantstransformedwithδ9desaturasegenedesC::licBM3lackingsignalsofintracellulartargetingwhileexpressionofthisgenewithArabidopsisthalianaRubiscosmallsubunittransitpeptidesequencecausedgrowthofC18:3α-linolenicacidpartsimultaneouslywithreductionofC18:2linoleicacidpart,aswellasincreaseofunsat-urationindex.Nochangesinrelativeamountofδ9-monounsaturatedfattyacidswereobservedinanyofstudiedlines.Allplantsexpressingdesaturasegenesexhibitedenhancedlevelsofsuperoxidedismutase(SOD)activityaftercoldtreatmentincontrasttocontrollineswithsuppressedSODactivityaftercoldtreatment.
Improvementofenzymeactivityofβ-1,3-1,4-glucanasefromPaenibacillussp.X4byerror-pronePCRandstructuralinsightsofmutatedresidues.
Baek,S.C.,Ho,T.H.,Lee,H.W.,Jung,W.K.,Gang,H.S.,Kang,L.W.&Kim,H.(2017).AppliedMicrobiologyandBiotechnology,101(10),4073-4083.
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β-1,3-1,4-Glucanase(BGlc8H)fromPaenibacillussp.X4wasmutatedbyerror-pronePCRortruncatedusingterminationprimerstoimproveitsenzymeproperties.ThecrystalstructureofBGlc8Hwasdeterminedataresolutionof1.8Åtostudythepossiblerolesofmutatedresiduesandtruncatedregionsoftheenzyme.Inmutationexperiments,threeclonesofEP2-6,2-10,and5-28werefinallyselectedthatexhibitedhigherspecificactivitiesthanthewildtypewhenmeasuredusingtheircrudeextracts.EnzymevariantsofBG2-6,BG2-10,andBG5-28weremutatedattwo,two,andsixaminoacidresidues,respectively.TheseenzymeswerepurifiedhomogeneouslybyHi-TrapQandCHT-IIchromatography.SpecificactivityofBG5-28was2.11-foldhigherthanthatofwild-typeBGwt,whereasthoseofBG2-6andBG2-10were0.93-and1.19-foldthatofthewildtype,respectively.TheoptimumpHvaluesandtemperaturesofthevariantswerenearlythesameasthoseofBGwt(pH5.0and40°C,respectively).However,thehalf-lifeoftheenzymeactivityandcatalyticefficiency(kcat/Km)ofBG5-28were1.92-and2.12-foldgreaterthanthoseofBGwtat40°C,respectively.ThecatalyticefficiencyofBG5-28increasedto3.09-foldthatofBGwtat60°C.TheseincreasesinthethermostabilityandcatalyticefficiencyofBG5-28mightbeusefulforthehydrolysisofβ-glucanstoproducefermentablesugars.OfthesixmutatedresiduesofBG5-28,fiveresidueswerepresentinmatureBGlc8Hprotein,andtwoofthemwerelocatedinthecorescaffoldofBGlc8Handtheremainingthreeresidueswereinthesubstrate-bindingpocketformingloopregions.Intruncationexperiments,threeformsofC-terminaltruncatedBGlc8Hweremade,whichcomprised360,286,and215aminoacidresiduesinsteadofthe409residuesofthewildtype.Noenzymeactivitywasobservedforthesetruncatedenzymes,suggestingthecompletescaffoldoftheα6/α6-double-barrelstructureisessentialforenzymeactivity.
Oligomerizationtriggeredbyfoldon:asimplemethodtoenhancethecatalyticefficiencyoflichenaseandxylanase.
Wang,X.,Ge,H.,Zhang,D.,Wu,S.&Zhang,G.(2017).BMCBiotechnology,17(1),57.
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Background:Effectiveandsimplemethodsthatleadtohigherenzymaticefficienciesarehighlysough.Hereweproposedafoldon-triggeredtrimerizationofthetargetenzymeswithsignificantlyimprovedcatalyticperformancesbyfusingafoldondomainattheC-terminusoftheenzymesviaelastin-likepolypeptides(ELPs).Thefoldondomaincomprises27residuesandcanformstrimerswithhighstability.Results:Lichenaseandxylanasecanhydrolyzelichenanandxylantoproducevalueaddedproductsandbiofuels,andtheyhavegreatpotentialsasbiotechnologicaltoolsinvariousindustrialapplications.Wetookthemastheexamplesandcomparedthekineticparametersoftheengineeredtrimericenzymestothoseofthemonomericandwildtypeones.Whencomparedwiththemonomericones,thecatalyticefficiency(kcat/Km)ofthetrimericlichenaseandxylanaseincreased4.2-and3.9-fold.Thecatalyticconstant(kcat)ofthetrimericlichenaseandxylanaseincreased1.8-foldand5.0-foldthantheircorrespondingwild-typecounterparts.Also,thespecificactivitiesoftrimericlichenaseandxylanaseincreasedby149%and94%thanthoseofthemonomericones.Besides,therecoveryofthelichenaseandxylanaseactivitiesincreasedby12.4%and6.1%duringthepurificationprocessusingELPsasthenon-chromatographictag.ThepossiblereasonisthefoldondomaincanreducethetransitiontemperatureoftheELPs.Conclusion:Thetrimericlichenaseandxylanaseinducedbyfoldonhaveadvantagesinthecatalyticperformances.Besides,theywereeasiertopurifywithincreasedpurificationfoldanddecreasedthelossofactivitiescomparedtotheircorrespondingmonomericones.Trimerizingofthetargetenzymestriggeredbythefoldondomaincouldimprovetheiractivitiesandfacilitatethepurification,whichrepresentsasimpleandeffectiveenzyme-engineeringtool.Itshouldhaveexcitingpotentialsbothinindustrialandlaboratoryscales.
品牌介绍
Megazyme品牌产品简介
来源：作者：人气：2149发表时间：2016-05-19 10:59:00【大 中 小】
Megazyme是一家全球性公司，专注于开发和提供用于饮料、谷物、乳制品、食品、饲料、发酵、生物燃料和葡萄酒产业用的分析试剂、酶和检测试剂盒。Megazyme的许多检测试剂盒产品已经为众多官方科学协会（包括AOAC, AACC , RACI, EBC和ICC等），经过严格的审核，批准认证为官方标准方法，确保以准确、可靠、定量和易于使用的测试方法，满足客户的质量诉求。
Megazyme的主要产品线包括：
◆ 检测试剂盒
◆ 酶
◆ 酶底物
◆ 碳水化合物
◆ 化学品/仪器
官网地址：http://www.megazyme.com
检测试剂盒特色产品：
货号
中文品名
用途
K-ACETAF
乙酸[AF法]检测试剂盒
酶法定量分析乙酸最广泛使用的方法
K-ACHDF
可吸收糖/膳食纤维检测试剂盒
酒精沉淀法测定膳食纤维
K-AMIAR
氨快速检测试剂盒
用于包括葡萄汁、葡萄酒以及其它食品饮料样品中氨含量的快速检测分析。
K-AMYL
直链淀粉/支链淀粉检测试剂盒
谷物淀粉和而粉中直链淀粉/支链淀粉比例和含量检测
K-ARAB
阿拉伯聚糖检测试剂盒
果汁浓缩液中阿拉伯聚糖的检测
K-ASNAM
L-天冬酰胺/L-谷氨酰胺和氨快速检测试剂盒
用于食品工业中丙烯酰胺前体、细胞培养基、以及上清液组分中、L-天冬酰胺，谷氨酰胺和氨的检测分析
K-ASPTM
阿斯巴甜检测试剂盒
专业用于测定饮料和食品中阿斯巴甜含量，操作简单
K-BETA3
β-淀粉酶检测试剂盒
适用于麦芽粉中β-淀粉酶的测定
K-BGLU
混合键β-葡聚糖检测试剂盒
测定谷物、荞麦粉、麦汁、啤酒及其它食品中混合键β-葡聚糖(1,3:1,4-β-D-葡聚糖)的含量
K-CERA
α-淀粉酶检测试剂盒
谷物和发酵液（真菌和细菌）中α-淀粉酶的分析测定
K-CITR
柠檬酸检测试剂盒
快速、可靠地检测食品、饮料和其它物料中柠檬酸（柠檬酸盐）含量
K-DLATE
乳酸快速检测试剂盒
快速、特异性检测饮料、肉类、奶制品和其它食品中L-乳酸和D-乳酸(乳酸盐）含量
K-EBHLG
酵母β-葡聚糖酶检测试剂盒
用于测量和分析酵母中1,3:1,6?-β-葡聚糖，也可以检测1,3-葡聚糖
K-ETSULPH
总亚硫酸检测试剂盒
测定葡萄酒、饮料、食品和其他物料中总亚硫酸含量（按二氧化硫计）的一种简单，高效，可靠的酶法检测方法
K-FRGLMQ
D-果糖/D-葡萄糖[MegaQuant法]检测试剂盒
适用于使用megaquant?色度计（505nm下）测定葡萄、葡萄汁和葡萄酒中D-果糖和D-葡萄糖的含量。
K-FRUC
果聚糖检测试剂盒
含有淀粉、蔗糖和其他糖类的植物提取物和食品中果聚糖的含量测定。
K-FRUGL
D-果糖/D-葡萄糖检测试剂盒
对植物和食品中果糖或葡萄糖含量的酶法紫外分光测定。
K-GALM
半乳甘露聚糖检测试剂盒
食品和植物产品中半乳甘露聚糖的含量检测
K-GLUC
D-葡萄糖[GOPOD]检测试剂盒
谷物提取物中D-葡萄糖的含量测定，可以和其它Megazyme检测试剂盒联合使用。
K-GLUHK
D-葡萄糖[HK]检测试剂盒
植物和食品中D-葡萄糖的含量测定，可以和其它Megazyme检测试剂盒联合使用。
K-GLUM
葡甘聚糖检测试剂盒
植物和食品中葡甘聚糖的含量测定。
K-INTDF
总膳食纤维检测试剂盒
总膳食纤维特定检测和分析
K-LACGAR
乳糖/D-半乳糖快速检测试剂盒
用于快速检测食品和植物产品中乳糖、D-半乳糖和L-阿拉伯糖
K-LACSU
乳糖/蔗糖/D-葡萄糖检测试剂盒
混合面粉和其它物料中蔗糖、乳糖和D-葡萄糖的测定
K-LACTUL
乳果糖检测试剂盒
特异性、快速和灵敏测量奶基样品中乳果糖含量
K-MANGL
D-甘露糖/D-果糖/D-葡萄糖检测试剂盒
适合测定植物产品和多糖酸性水解产物中D-甘露糖含量
K-MASUG
麦芽糖/蔗糖/D-葡萄糖检测试剂盒
在植物和食品中麦芽糖，蔗糖和葡萄糖的含量检测
K-PECID
胶质识别检测试剂盒
食品配料中果胶的鉴别
K-PHYT
植酸(总磷)检测试剂盒
食品和饲料样品植酸/总磷含量测量的简便方法。不需要通过阴离子交换色谱对植酸纯化，适合于大量样本分析
K-PYRUV
丙酮酸检测试剂盒
在啤酒、葡萄酒、果汁、食品和体液中丙酮酸分析
K-RAFGA
棉子糖/D-半乳糖检测试剂盒
快速测量植物材料和食品中棉子糖和半乳糖含量
K-RAFGL
棉子糖/蔗糖/D-半乳糖检测试剂盒
分析种子和种子粉中D-葡萄糖、蔗糖、棉子糖、水苏糖和毛蕊花糖含量。通过将棉子糖、水苏糖和毛蕊花糖酶解D-葡萄糖、D-果糖和半乳糖，从而测定葡萄糖含量来确定
K-SDAM
淀粉损伤检测试剂盒
谷物面粉中淀粉损伤的检测和分析
K-SUCGL
蔗糖/D-葡萄糖检测试剂盒
饮料、果汁、蜂蜜和食品中蔗糖和葡萄糖的分析
K-SUFRG
蔗糖/D-果糖/D-葡萄糖检测试剂盒
适用于植物和食品中蔗糖、D-葡萄糖和D-果糖的测定
K-TDFR
总膳食纤维检测试剂盒
总膳食纤维检测
K-TREH
海藻糖检测试剂盒
快速、可靠地检测食品、饮料和其它物料中海藻糖含量
K-URAMR
尿素/氨快速检测试剂盒
适用于水、饮料、乳制品和食品中尿素和氨的快速测定
K-URONIC
D-葡萄糖醛酸/D-半乳糖醛酸检测试剂盒
简单、可靠、精确测定植物提取物、培养基/上清液以及其它物料中六元糖醛酸含量（D-葡萄糖醛酸和D-半乳糖醛酸）
K-XYLOSE
D-木糖检测试剂盒
简单、可靠、精确测定植物提取物、培养基/上清液以及其它物料中D-木糖含量
K-YBGL
Beta葡聚糖[酵母和蘑菇]检测试剂盒
检测酵母和蘑菇制品中1,3:1,6-beta-葡聚糖和α-葡聚糖含量
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