hello everyonewelcome to my presentation today i amyoungi'm the lead scientist from chemicaldevelopment department from fairingpharmaceuticals indenmark the title of my presentationtoday is the peptide set reactions anddegradationsand part of the contents from mypresentation today iscited in my book site reactions inpeptide synthesisif you're interested you'll recommend itrefer to the book for further readingi my presentation today will be splitinto two parts the part one is aboutside reactions in peptide synthesis andpart twois about the peptide instability anddegradationsso the first part is also categorizingto two groupsthe first part is about the sidereactions in the peptide assemblyand the second part is the set reactionsin the peptide cleavage and globaldeprotectionthe first categories of the sidereactions in the peptideassembly is about endo impurities soendo impurities meansin the peptide assembly some certainamino acids is incorporated twiceso for example this peptide it has two xa m minus two residues so we call thisimpurities and x a and minus twothe reason of this impurities uh hassomecourses the first one is the f mark xaxa a die peptide impurities in thestarting materialor the unprotectedxaa impurities english starting materialora the exhibition ranging after the fmark xaacoupling which is can also introduce theendo impuritiesthe fourth categories of the reason isthe premature f marked blocking so thisanime animation isillustrating this mechanism during theassembly of the xaait's coupled to the peptide howeverunder whatever reasonsthe f mark could be prematurely cleavedoff during or before thecouplings and if this unprotected aminoacid is coupled to the peptideresins its free amino groups can allow afurther coupling of the anothermolecules making these endo impuritiesthe reason of this premature f markblocking could be thepresence of some basic motives like thelysine amino epsilon inducedf marked blocking or the uh n alphaamino groups from the proline or the dmfsome dmf can contain levels ofdimethylamine which can cleave f markduring the couplingsor the rescue preparingcan also remove the f mark if thepreparing is notthoroughly washed away after f markedblockinga ubiquitous anal annual impurities istheendo xaac terminal is normally addressedctc resinthe mechanism is that when thepenultimate amino acid is activated bydic and further by hovtthe formed hobd ester is addedto the amino acid resins togive the target dipeptidehowever even though hobt is usingthe catalyst in the reactions it's inexcessand the excess hovt can cleavethe first amine acid off the resinsso the stability of the amino acidsis much weaker than the full sequencessoit could be partially cleaved by thehobtand release to the reaction mixturesand the released amino acids can reactwith the amino acid resins to form thedipeptideand in the presence of the huel excessof thepenultimate amino acidsthe endo impurity will be formedand this mode of the endo impurities ispredominantly address the ctcresins because of its high acidsensitivitiesand the sum of the amino acids like theproline or glycine when theyserve against the c-terminal residuesthey are more susceptible to suchpremature acidosis compared to the otheramino acidsand the mold of the activation of thepenultimate amino acids very criticalso the process parameters like theactivation temperaturesproactivation time and couplingtemperatures are very criticalfor the formation of the endo xaaimpuritiesthe second categories of the impuritiescommonly addressed peptide assembly iscalledxa impurities so this means someamino acids is deleted from thesequences and weform this tests for example xaa and -3impuritiesthe reason of this death computer isnormally because of the incompletecoupling of the specific amino acidsso the potential solution to address itis through the recouplingand using stronger coupling reagentsenhance the equivalence of the reactantschange the solvents enhance the reactiontemperaturesuse catalysts like the d-map for thecouplingsand reduce the rising loading ratebecause of the low rate loading rate thecoupling kinetics could beenhanced or using a catatropicsalt like the potassium bromideor using the dipeptide building blocksto bypass the formations of thisxaa impurities another reason for thistest impurities is theinsufficient proceeding f multiblockingso the fmark is not fully removed of the resinsby preparating and therefore when youcouple the second amino acid of coursethesite is blocked and can impede thecoupling of that amino acidthe solution to address this course isto increase the basetreatment circles like normallythey treat by two times we can enhanceto three times orfull time as needed to completely removethe f markor to address the to use the highertemperatures for the f modblocking using stronger base like thedbuto remove the fthe third group of the set reactions inthe peptide assembly is called dicend capping in theindustry peptide assembly dic is thecoupling regionby default because of the cox advantagesthe amino acid is normallyactivated by the dic to thecorresponding dic estersand this is added to the peptide resinsto coupleand form the pipette bond however inexcess of thecoupling rate dic and if the couplingreactions kinetics is slowthe probability of the reactions betweenthe dicand the alpha amino groups on therussians is enhancedand thus forming this guanine dean saidreactions we call thisdic end capping it formsimpurities with 126 molecular weightincrementcorresponding to the targetedintermediatesin case of the depth of peptide theformed dic and capping periods canmediate the intramolecular cyclizationto form theimmunohedantoin impuritiesthe fourth categories of the sadreactions is calleddkp formations is the the ketopiparasiteis very common ubiquitous set reactionsin the peptide assemblythis rectangle because of thenucleophilicities of the alpha aminogroups it canattack the peptide bond of its ownmolecules to form this dkprings and chopping off the seed at theof the die peptide making this truncatedsequencesand we call this dkp formationsit could either be formed during themanufacturing processes orduring the formulations and storage isregarded as the degradations impuritiesand dkpset reactions is predominantly occurredunder basic conditions it prevails atthe f mark the blocking stepsand it's very strongly related to thetype of the secondary base likepreparating piperazineand solvents for the f mark removalit's high it's highly temperature andtime dependentand it has some significant scale-upeffects if they prolongeda case of the prolonged whole timebetween the coupling and the f multiblockingit could generate some enhanced degreesof the dkpformations and it could also occurin the api manufacturing austin storageeven asthe solid and during the formulationsit's verysequence dependent so the c miconfigurations promote the this dkpformationsfor example if it has the uh the naccu amino acids like the xa poolingpepper bondor the c alpha alpha diaculated aminoacids like the aibor the glycine is on thec to the n terminals like a glycineglycine is very highlydkp prone also when glycine is on thethirdposition from the n-terminus the dkp isenhancedhasting proline is prone to dkpformation as welland the alternating configuration of theamino acids like the land d o d and l are also very prone todkp formations so here is a question foryouso what if the dkp information isoccurredat the c terminus of the dipeptide onctc is rising so what's theconsequence will bethe aspartate information is alsonotoriously known as the side reactionsin the peptide thicknessesthis is because of the nucleophilicitiesof the atomite nitrogens it can attackthe carboxylate groups on the asparticside chains to form this aspartameintermediateswhich can energize the um glycophyllicattackeither by waters or preparation if atthethis site hydrolyzed by by waterit can um transform be transformed intothe aspartic aciduh l and d because of the rasterizationcan occurat the steps of the aspartame formationsif it's uh attacked by the preparationit will form the aspartic acid paradisewith m plus67 molecular weight increasementsand if this attackoccurs at the site b hereit will form the iso aspartic acid orthe iso aspartate gases preparationimpuritiesasparagus as part of malformation couldbe catalyzed by bothacid and base and its accumulativeformations it canoccur all the way along as long as theaspartic acid is introducedit could be taking place at the steps ofthe peptide synthesis formulationand storage it can also addressthe protected aspartic acid and theprotecting groups has very significantimpacts onaspartate gas inflammation for thepeptide assembly it's highly sequencedependentso when is the second amino acid glycineorserine throning ironing asparagineaspartic acidhasting or it has the alternatingconfigurations likel-aspartia d amino acid ord-aspartic acid l-amino acids theprobability ofaspartame formation is increasedglutamic acids can also undergo similarreactions but toa much lesser extent umit's need to be highlighted here thatsome of thepeptide modifications like the sidechain to side chaincircularizations could alsoinduce some aspartate aspartamideformationsand when the carboxylate groups onosbotic side chains has activatedcorresponding active asterit can react with the amino groups hereto form the targetside chain sighting cyclization but onthe other sidethe probability of the aspartic aspartinformationis also increased because of theactivations of thesecarboxylic groupsasparagine diamination is also a wereknown set reactions in peptidethicknesses sothe us purging capoximiniteside chains is transformed to thecorresponding carboxylate groupsand of course the m plus one impuritiesthe mechanism of the the ammunitioncouldgo by the aspartic acid aspart of my deformations to form thisaspartateintermediate first and when thehydrolysis is taking place athere or here it will generate theaspartic acid or the iso aspartateanswerthis set reaction is regarded as themost pronounced decompositions of thepeptide drugs and it can proceedeither in low ph within low phit could go viral directly hydrolysis orhigh ph neutral ph maybe go virally asuh as part of my formations and it'shighly sequence dependentas protein gly asparagine glycineor searing throttling histine lysinetryptophan aspartic acid glutamateare more moresusceptible to the applicationsit's a temperature iron ironic strengthsolvent and viscosity dependenceit could be occurring the peptidethicknesses purificationslocalizations formulations and storageand itneed to be noted that the side chains ofthe asparasparagine can also attack the backboneof the peptide toto form this succinamide peptideand give the fragmentation of thepeptidesso the second part of the side reactionsin the peptide synthesis is thesad reaction during the peptide cleavageand globalthe first one says acculations someamino acids like the uh tryptophan ishighly prone to activateacculations by the for example thetributary cations from the protectinggroups orit's a tfa ester to form the mutilatedtryptophan impurities umcysteine can also be susceptible to theacculations by the tubule to form thetributary cysteineon the mercaptan groups and some of thepeptide linkerresin linkers if it is apparentlycleaveduh like the at the power ratings or thering camera resinsor ring mbha resins if this is clippedat theside of the linker sideit can generate different types of thecationsand these contains could make thealkylations on somesome susceptible residues like thetryptophan here it can generatedifferentacculated computers with plus 202106 163 and265 impurities byanother types of the cell reactions inthe peptide cleavage and globalprotections is the adducts umtryptophan for example could be undergomodifications by thetfa and edt to the impuritiesof m plus 72and also the edt can modify the sustainto form the m plus 92impurities with their structuresum the existing acmprotecting groups could be uhprematurely cleavedby tfa in the presence of the scanmanagers like theedt and form thethe system and could be further modifiedby the edt to the correspondingimpuritiesand also searing could be modified bythepbf protecting groups from the arginineto form the sulfonated impurities with mplus80 molecular weight incrementoxidation and reductions can occurduring the peptide cleavage and globalprotections the histamine tryptophanterracingsustained methionine could be oxidizedto corresponding oxidized degradationsand also the dimerizations of thetryptophan for examples could also occurduring theoxidations to form the dimers of thetryptophansome amino acid residues which is mostlyaromatic one are like the terracinghastings tryptophanthromolanines fluoroalaninesand pyruvate ironings could besubjected to the alternations in thepresence of the t3and aldine corresponding alternatedimpuritiesreductions in the peptide assemblycleavageis not very predominant but the sum ofof the amino acids like the trip fan canbe reduced by the triathlon to thecorrespondingdegradations with n plus two molecularweight incrementsand methylated or ethylated tyrosine forexamples can besubjected to the d-methylationd-ethylations bythe uh cell anisoleto form this corresponding terracingimpurities with m plus 14molecular weight decreasements disulfidecan be reduced by tfaum actually in the tfa byselene to corresponding mercaptan pairnow we come to the second part of mypresentation is about the peptideinstability and the degradation ofcourse it's intertwined with the sidereactions in peptide thicknessesbut this part i will focus on theinherent properties of the peptidemoleculesand the degradations mostly in thepipette formulationsand peptide instability predictions isvery critical forpharmaceuticals because it is veryusefulfor drug discoveries and toassess which potential drug candidatescould beunstable it is very helpful forguide the api manufacturabilityassessment to understandwhich manufacturing processes candegrade the peptideit is helpful to predict the stabilityof the peptidon storageand to guide the development of thecorresponding analytical methods todetectcertain peptide gradients it's also veryusefulfor drug product manufacturabilityassessments as wellso the part two of the peptideinstability predictionsis grouped into six categoriespepto hydrolysis peptide rearrangementscirculation fragmentations pet peteliminationspeptide adducts peptide cross linkingandsolvent induced peptide degradationpeptide hydrolysis is very common in thepeptide degradations the first part isabout thens acetyl and acute peptide hydrolysisthis small disease is pretty prone tohydrolysislike the accelerated soccer thingsthe mechanism is that they canform this uh five member rings5 hydroxyl ox zodiumand chopping off the n-terminal aminoacids making the truncated sequenceswhen an aqib residues is located in theinternal sequence of the peptide it cantriggeracetolosis the mechanism is that itinitiates such a nucleophilic attackthrough the full formations of thesefive memory intermediatesand cleaving the peptide at the site ofthe aiband c terminals for example this cyclicpeptidebearing and a methyl aib residuesit's hydrolyzed at this siteby tfa to cleave thecyclic peptide into the correspondinglinear peptidethe third categories of the hydrolysisis on the cterminals where it has the n-methyl xaait is more prone to acidosisfor example this mode is with then-methylc-terminal residues and the m-bond hereis more labeled to cleaving off theamino acids to forming thispipette impurities the mechanism is thatthe carboxylate groups on thec terminals could attack the mi bondhere because of theadvantages conformations at this peptidebondand forming these five membraneactivities and rearrange to thecorrespondinganhydride and cleaved by the acids tothe corresponding peptideacidssearing or surrounding and the internalsequence of the peptidecould also also drive thehydrolysis because of the nuclearvelocitiesof the hydroxyl group here it can attackthe preceding pipette bondat this site to form the five membraneintermediateswhich rearrange to the correspondingesters and this esters is hydrolyzed tothe peptideat the site of the searingthe sink uh could also catalyze thehydrolysis of the hastingand searing sequences tolock the peptide into an advantageousconformations that promoting theum nucleophilic attackfrom the cell rings to form these fivememory intermediatesand cleaving off the peptide bond hereto form thehydrolysisaspartic acid can mediate peptide bondhydrolysisasp pro is a notoriously known sequencefor its highacidosis propensities the aspartic acidand proline peptide bond could becleaved in the presence of the acids toform the aspartic acidand proling fragments aspsearing sequence is also prone tohydrolysis due to the advantageshydrogen bond here which chopping offthepeptide bond at the side of theasparagus and serumsand also aspartate gases can attackthe amide bond preceding amide bonds toform the six membrane intermediateswhich rearrange to the anhydride andhydrolyzed to the two partshaste pro sequence is also prone tohydrolysis when it's located on then-terminus of the peptideto chop off this hast pro fragments andform the impurities withm plus two three four in molecularweightthe e imidazole side chains of thehistidinemight be involved in this process tocleave off the hispros dipeptide by means of the dkpand form the fragmentation of thepeptidewhen asparagine or isosparging islocated on the cterminals of the peptide they are proneto hydrolysisto form the corresponding ionic to theacid this might be due to thehydrogen bond between the side chain andbackbones of the peptideand promote the water attack on theatomized bond to form the correspondingacidan alternative mechanism is that thecarboxylate cterminals can attack the amidebound on the side chains to form thesuccinate anhydridewhich is hydrolyzed subsequently to thecorresponding aspartic acidscarbinolamine and carbonylamide are veryprone to hydrolysis even thoughsuch motives are sometimes present insome peptide moleculesum cabin is this structures it'ssynonymous tohemi amino and carbinolamide isthe amide form of the carbonyl domainand carbon domain is pretty prone tohydrolysis to the correspondingamine and aldehyde or alternativelyit could be dehydrated to the e meanand cabinet amount similarly it veryprone tohydrolysis to give the correspondingamideby releasing the aldehydeenamite and dehydroalamine are prone tohydrolysisthese are the structures of thedehydroalanineand enamite the edamitecould be hydrated to the correspondingcarbinolateand we know that carbinolamide are notstable and could be hydrolyzed to thecross bonding ionideand ketone this is a concrete exampleof the hydrolysis of the dehydroalanineit could be hydrated first to thecorrespondingcarbonylamide and carbonylamide could behydrolyzed to the correspondingiodide and here is the empirevial peptidethe next categories of the peptidedegradationis the rearrangement so the firstexamples is theno also migrations we know that as cytogroups can migratebetween the amino groups and the hydroxygroupfor example when we have the acetylserines on the peptide and terminalsthe acetyl groups can migrate betweenthese two motives depend on the phfrom the isomer of the osu or n-acylas isomer so pay attention to thesequence of then-accept accelerated seriesand also the depth of peptide when itappears atamino groups the acetyl groups canmigratefrom the uh hydroxyl group to the aminogroups to form the correspondingionic isomers so also pay attention tothe depth c peptide bearing alpha aminogroupand also the serine could be modified bythetfa to corresponding tfa esters and thisafter this uh trifluoroacetylgroups can also migrate from thehydroxyl group to the amino groupto form the sort of the irreversible umtfa acetylated impurities with molecularweight increasementof 96next we will talk about the end-to-endiso migrationssome amino acids like the diaminopropionic acidsdpr for short the dab whichis the diaminoburic acids or the otherthingsare prone to such a rearrangement forexamplesthe dpr is prone to accommodate theiso migrations from the backbone to theside chains while these five membraneintermediatesto form the corresponding isomersand once the dab is concerned it has thetwo probabilities of the migrations oneroot a oneroot b and root a it forms this isomersandroot b it's lead to the fragmentationsof theof the peptide and these twomigrations are very risky because itgenerates a isomers and sometimesif you don't have the reference of theisomers this kind of migrations canignore your detections we have thisexperience that sometimes when you don'tmake the reference of the impuritiesthis degradationis escaped from being detectedand also other things can lead to theelectronizations bythe similar degradation pathways to formthefragmentations of the peptide and ithink the nature selects the licenseoverother things the b and dpr has somereasonsand this might account for why thelysineis a selectednextly we talk about the end-to-endcopper moisture migrationscarbon molecule is sometimes in thepeptide drugsand carbon moisture can migrate from onevoltageto the other by thismechanism to form the thecopper mole migrations and aromatic ureafor examples if the middle groups hereis linked to aromatic residuesthis kind of the migrations is moreprobable to occuruh next we'll talk about the peptideeliminationsso the electron withdrawingsubstitutions on thebigger positions for example here is thebeta positionswhere it has electron withdrawing groupsthe probability of theelimination is high and this is reasonwhy we call it beta eliminationsand beta eliminations can occur in thebasic conditionsthrough the e1cb mechanismit forms the dehydral adeninesand corresponding adductsso beta eliminations can occuron the system residueswhen it has some protecting groups hereum and in presence of the preparationthis mobilities could be cleaved offand form the correspondingdehydroalanine degradantsfor examples in the assembly of thepeptide and when the systemis located on the c terminals and it'svery prone tobeta eliminations to form thecorrespondingand prepared then can react with thatby means of the microadditions to formthe correspondingpreparation impurities with m plus 51.disulfide is prone to beta eliminationas wellthis is the mechanism in the presence ofa basedisulfide and it goes beta eliminationsto form the dihydroalanine andpresulphideand prosulfite can be degraded to thesustain and sulfuror alternatively it could be hydrolyzedto the correspondingsulfatic acid and sulfatic acidcan be disproportionatedisproportionated intoa cysteine and safinic aciddisulfide can also accommodate betaeliminations to giverise to the formation of the erasmicdisulfidetrisulfide and lethaling or monosulphitethe two molecules of the disulfidescan undergo disulfide scrambling to givethedimers and dimers can further undergobeta eliminations uh giving two motivesbearing the dehydroalanine andprosulfite respectivelyand for the presultified peptideit can undergo trisulfide formations togive the trisulfidewhile rest for dehydroadenine it cangivelandfilling by the microadditions oralternativelythe um dehydrogenating canundergo hydrolysis and form thecorresponding and provide pyruvatepeptidedisulfide peptide can also undergobetter eliminations toform the dehydroalanine and prosulfiteand this can reshuffle to the disulfideby micro additions but give to therasterizationsso in total four types of thedegradations can be generated by thedisulfidebeta eliminationnext we will talk about peptide adductsthe first categories of the adducts isthe acculationsthe peptide could be modified by theformaldehydecorresponding intermediates withmolecular weightm plus 30 and this derivatives could befurther dehydrated to the correspondingshift base of the m plus 12.when these modifications occurs on thepeptide and terminalsthe formed sheath base could be cyclizedto the correspondingimidazolidinal also m plus 12.some amino acids like the cysteine ortryptophanor asparagines or histaminescould also undergoes different type ofthe cyclization to form thecorresponding and plus 12impurities also theformaldehyde and presence of theformic acids can accommodate isola clarkreactions to formthe acculations of the mineral groups oreven thedye alkylation of the amino groupsnext we will talk about the peptidesaturations peptide saturations could becatalyzed by acetic acid in the presenceof theethyl acetate to form the correspondingacetylated peptideand also histidine can catalyze theacetylations we know thatimidazole is a good catalyst for acidmigrationsand also the histidine can catalyze thiskind ofreactions to form the firstlyaccelerated histidineand the cyto groups can migrate from thehistidine to the corresponding aminogroups togenerate the acceleration's impuritieswe know that urea sometimescan be a fastly even fastly degradedcorresponding sciatic acidsand in the process of the carboxylategroups it forms the correspondingcarboxylic acidcarbomic acid mixed anhydride andonce this antiderive is formed it canmodifythe amino groups and to form thecorresponding and acetyl-amineimpuritiesand releasing the dicarbon dioxideammoniumthe next categories of the adducts isthe peptide coupled modulationsthe capacitance can be triggered by theureaas well and the urine can form the crossbonding isothermic acidand it can give the amino degraded tocrest bodyammonium the carbon dioxideand once these isosonic acids formedit can modify a varieties of the peptideincluding the mineral groupsthe cysteines the histidinesand carboxylate groups and pterosanesand arginines and phosphoric acidto form the corresponding carbomolationsimpuritiesnextly we talk about the peptidecrosslinking to form dimers or multimersthe first categories is thetransaminationsand we know that the transformations cantake place between the amino groupsand imi to form the transformed imideand amine and if this transformationtakes place between two moleculesone molecules compare contains aminogroups the other onehas a correspondingcarboxymite and this kind oftransformations willlead to the formations of the of thedimerwith molecular weight two times of themonomers minus17 because uh one molecules of ammoniumis kicked out oftherenextly we talk about aspartamide inducedcrosslinkingaspartame can take placeon a aspartic acid containing peptideand once theaspartamide is formed it could bealso attacked by the amino group fromanother peptide moleculesto form the dimers of the peptideimpuritiesdepending on the attack pathwaysalso the succeeding and dendrite caninduce cross-linking as wellif the the asparagine c-terminalresiduesis formed the correspondingcinnamic acid anhydride it could beattacked by the amino group from othermolecules to form thethe dimers for example the insulin canform the insulin dimersby this mechanismbeta eliminations can also lead to thecross-linking of the peptidefor examples if the beta elimination isaddressing a peptide it will form thecorresponding dehydrogen motifsand this could be attacked by anotherpeptide molecules by the microaddictionsto form thethe dimers herewe show that the dehydrogenating couldbe reacting withthe lysines with histamines or withsystems to form the different kind oftheof the diameter combinationsin disulfide is definitely a hotspot forcrosslinking disulfide could be degradedin the presence of the trace of thelinearsustain peptide impuritiesto form the dimer and dimer is already across linkingbut the dimer could further undergo bigeliminationsand give the corresponding peptides withcysteineand prosulfite and this can furtherundergo someintermolecular cross-linking to give thedifferent types of the cross-linkingimpuritiesalternatively this dimer itself can givehigh odors of oligomers through thefurther ethanoldisulfide exchangealternatively the dissolve fat itselfcan negotiate eliminations to give thepresulfireand the hydroaldening here andit can undergo desulphurizations to formthe system and this thing canundergo further cross-linkingdisulfide can also undergo alphaeliminations in present waters to formthemercaptans and cyphenic acidand suffering acids can undergoesfurther cross-linking by theta disulfideexchange etc to form the different typesof the cross-linking degradationsso it's very critical to control thelevels of the linearimpurities in a disulfide peptides forexamplesometimes of the peptide is very verysensitive tothe um to the captain impurities andthe uncontrolled organizations can takeplaceduring the formulations because of thismechanismpeptide oxidation can sometimes lead tocross-linkingfor example histidine could sometimes beoxidized to the corresponding forhydroxy to oxalyl histidineand this derivatives can react with alot of theamino acid abilities for exampleargininehistidine lysine andsustain and form the correspondingthe dimeric impurities um through thecross-linking between the hassling andthecorresponding nucleophilic amino acidsnext we will talk about uh thesolvent-induced peptide gradations thefirst one is the dichloromethanedichromating is relatively an inertorganic solvent but it's nottotally ignorant in the presence of thepreparing for examplesdichromate thing can react withreparating preparing to form this is thegerminal degradations which canbe further degraded to the correspondinge mean or ammonium salt and ammoniumsource can be hydrolyzedto release the formaldehydealso the dichromethanes can be slowlyhydrolyzedand by releasing the hcl to theintermediates which can be furtherdegradedand give the formic acid uh sorry forformaldehyde and format could bedisproportionated to the cross bondingformic acid and the methanolnext we talk about dmf dmf is a rathercomplicated scenario and dmf cangive to the formulations of the aminogroup directlyor alternatively dmf can functions andreactants we know that emfcan work as a catalyst sometimesbecause of these nucleophilicities andin the presence of the strongelectrophiles for examples thephosphoryl chloridebmf can react with phosphoryl chlorideby means of the fisma hack reactions togivethis phase my rate and the intermediatesand we know that is prettyreactive towards different nucleophilesand can givethe ammonium salt intermediates which ishydrolyzed to corresponding formulationsof the nucleophilesnot only the phosphoryl chloride butalso otherelectrophiles for example like hbtucan be reactive towards the emf and theycan slowlyproceed involve the phase my hackreactionsand give to the formulations of the ofthenucleophile so it's giving the end mplus 82 formulations impuritiesacetone notch well certain nitrogencould be oxidized to the correspondingradicals and these radicals can reactwith the oxygens to formthose intermediates and this can befurtherdegraded and by releasing the waterto give this the formal solenoid andformula cell nut can reactfor example with the amine to form theum the formulations of the mean bygiving releasing their solenoidthe mso dmso can oxidize the variety ofthepeptides like the mechanical ethertryptophantertiary immune tyrosine etc anddmf itself can undergo somedegradations by radicalmechanism to form those intermediatesand this can givethe methyl radicals and thecorrespondingmethane suffinic acid and methylradicals can be trapped by oxygens togive the methyl peroxide radicalsand they can form the dimer by theterminationsbut they can further undergo the rootcell terminationsand give rise to the formations of theformaldehydeand formaldehyde can further triggerpeptide degradationsmethanol and tributal the methanol canreact with the carboxylate groupsto form the corresponding methyl esterand the traditional can undergo radicaldegradations to form these radicals andthey can form the dimersor alternatively they can form this kindof radicals on the oxygensand they can degrade it by releasingthe acetones and form the correspondingmethyl radicals and we have introducedin the preceding slides like themethyl radicals can further react withoxygens and to be degraded to theformaldehyde so formaldehydeand acetones can trigger some peptidemodificationsthen is acetones so acetones can reactwith thehistory with the hastenings especiallywhen hasting is located on the nterminals of the peptideand they give these intermediates of theadductswhich is the further dehydrated throughthe correspondinguh enamine the molecular weight isincreased by40. also theacetone can react with the n-terminalamino groups to form the intermediatesof the immune salt andit can undergo cyclizationintramolecularlyto form the immune diazolidinol it alsohas amolecular weight increasement of thefullyso that's all my presentations for todayandmany thanks for your attentions

以下為機(jī)翻

大家好，歡迎來到我今天的演講

我amyoungi 是來自fairingpharmaceuticals indenmark 化學(xué)開發(fā)部門的首席科學(xué)家

我今天演講的標(biāo)題是肽組反應(yīng)和降解，

我今天演講的部分內(nèi)容引用在我的書中多肽合成中的現(xiàn)場反應(yīng)

如果你感興趣的話'我推薦它參考這本書進(jìn)一步閱讀

我今天的演講將分為兩部分

第一部分是關(guān)于肽合成中的副反應(yīng)，第二部分是關(guān)于肽的不穩(wěn)定性和降解，所以第一部分也分為兩組，第一部分是關(guān)于肽中的副反應(yīng)組裝和第二部分是肽切割和全局去保護(hù)中的集合反應(yīng)

肽組裝中的第一類副反應(yīng)是關(guān)于內(nèi)切雜質(zhì)

所以內(nèi)切雜質(zhì)是指在肽組裝中某些某些氨基酸被摻入兩次例如這個肽它有兩個 xa m 減去兩個殘基所以我們稱其為雜質(zhì)和 xa 和負(fù)二這種雜質(zhì)的原因 uh hassome course 第一個是 f 標(biāo)記 xaxa 原料中的肽雜質(zhì)或未受保護(hù)的xaa 雜質(zhì)英文起始材料或展覽范圍在fmark xaacoupling 之后也可以引入endo 雜質(zhì)第四類原因是過早的f 標(biāo)記阻塞所以這個動畫動畫說明了xaait 組裝過程中的這種機(jī)制s 與肽偶聯(lián)，然而無論出于何種原因，f 標(biāo)記可能在偶聯(lián)期間或之前被過早切割，如果這種未受保護(hù)的氨基酸與肽樹脂偶聯(lián)，其游離氨基可以允許另一個分子進(jìn)一步偶聯(lián)，從而產(chǎn)生這些內(nèi)切雜質(zhì)。這種過早 f 標(biāo)記阻斷的原因可能是存在一些基本動機(jī)，如賴氨酸氨基ε誘導(dǎo)的顯著阻斷或脯氨酸或 dmf 中的 uhn α氨基基團(tuán) dmf 可能含有一定水平的二甲胺，在偶聯(lián)過程中可以切割 f 標(biāo)記，或者如果制備物沒有徹底清洗，拯救制備也可以去除 f 標(biāo)記f 標(biāo)記阻斷后遠(yuǎn)離肛門常年雜質(zhì)istheendo xaac 末端通常被處理ctc 樹脂機(jī)制是當(dāng)?shù)箶?shù)第二個氨基酸被dic 激活時并且進(jìn)一步通過將形成的hobd酯添加到氨基酸樹脂中以產(chǎn)生目標(biāo)二肽，但是即使hobt在反應(yīng)中使用催化劑s 過量和過量的 hovt 可以將第一個氨基酸從樹脂上裂解下來，因此氨基酸的穩(wěn)定性比完整序列弱得多，因此它可能被部分裂解并釋放到反應(yīng)混合物中，并且釋放的氨基酸可以與氨基酸樹脂反應(yīng)形成二肽并在倒數(shù)第二個氨基酸的huel 過量的存在會形成內(nèi)切雜質(zhì)，這種內(nèi)切雜質(zhì)模式主要針對 ctcresins，因?yàn)樗哂懈咚崦舾行裕⑶耶?dāng)它們對 c 末端殘基起作用時，它們是氨基酸的總和，如脯氨酸或甘氨酸，它們更容易受到影響對于這種過早的酸中毒，與其他氨基酸相比，倒數(shù)第二個氨基酸的活化霉菌非常關(guān)鍵，因此活化溫度、活化時間等工藝參數(shù)和偶聯(lián)溫度對于內(nèi)型 xaa 雜質(zhì)的形成非常關(guān)鍵。

第二類雜質(zhì)通常被稱為肽組裝物，稱為 xa 雜質(zhì)，因此這意味著從這些序列中刪除了一些氨基酸，我們進(jìn)行了此測試，例如 xaa 和 -3 雜質(zhì)，這臺死亡計(jì)算機(jī)的原因通常是由于不完全偶聯(lián)因此，通過重新偶聯(lián)和使用更強(qiáng)的偶聯(lián)劑來解決該問題的潛在解決方案提高反應(yīng)物的等價性改變?nèi)軇┨岣叻磻?yīng)溫度使用催化劑（如偶聯(lián)的 d-map）并降低上升的負(fù)載率，因?yàn)榈退俾守?fù)載率偶聯(lián)動力學(xué)可以改進(jìn)或使用像溴化鉀這樣的變質(zhì)鹽或使用二肽構(gòu)建塊繞過這個xaa雜質(zhì)的形成這個測試雜質(zhì)的另一個原因是多嵌段的進(jìn)行不夠，所以fmark沒有通過制備完全去除樹脂，因此當(dāng)你偶聯(lián)第二個氨基酸時，當(dāng)然該位點(diǎn)被阻塞并可能阻礙該氨基酸的偶聯(lián)解決這個問題的解決方案是像往常一樣將堿處理圈增加兩倍，我們可以根據(jù)需要將其提高到三倍或全部時間，以完全去除 f 標(biāo)記以解決肽組裝在行業(yè)中被稱為 dicend capping將相應(yīng)的二酯添加到肽樹脂中以偶聯(lián)并形成移液管鍵，但是如果偶聯(lián)率 dic 不超過，并且如果偶聯(lián)反應(yīng)動力學(xué)緩慢，則 dic 和 α-氨基之間的反應(yīng)概率會提高，從而形成這種鳥嘌呤，我們稱這種反應(yīng)為此 dic 封端 它形成分子量增加 126 的雜質(zhì) 對應(yīng)于目標(biāo)中間體 在肽深度的情況下 形成的 dic 和封端周期可以介導(dǎo)分子內(nèi)環(huán)化形成免疫 己內(nèi)酰脲雜質(zhì) 第四類反應(yīng)稱為 dkp 形成是酮體寄生蟲是肽組裝中非常常見的普遍設(shè)置反應(yīng) this長方形，因?yàn)?α 氨基的親核性，它可以攻擊肽鍵其自身的分子形成這個 dkprings 并在肽的末端切掉種子，形成這個截短的序列，我們稱之為 dkp 形成它可以在制造過程中形成，也可以在配方和儲存過程中形成，被認(rèn)為是降解雜質(zhì)，dkpset 反應(yīng)主要發(fā)生在堿性條件下在 f 標(biāo)記的封閉步驟中占主導(dǎo)地位，它與二級堿基的類型密切相關(guān)，例如制備哌嗪和去除 f 標(biāo)記的溶劑，它很高's 高度溫度和時間依賴性，如果它們延長耦合和 f 多嵌段之間的整個時間延長的情況，它具有一些顯著的放大效應(yīng)，它可以產(chǎn)生一些增強(qiáng)的 dk 形成程度，它也可能發(fā)生在 api 制造奧斯汀存儲中，即使是固體和在配制過程中's 非常依賴于序列，因此 c 錯誤配置促進(jìn)了這種 dkp 形成，例如，如果它具有 uh naccu 氨基酸，如 xa poolingpepper bond 或 c alpha alpha diaculated 氨基酸，如 aibor，甘氨酸在 c 到 n 末端，如甘氨酸甘氨酸非常高 dkp當(dāng)甘氨酸位于 n 末端的第三個位置時，dkp 也很容易發(fā)生 dkp 增強(qiáng)，脯氨酸也容易形成 dkp，并且像土地 dod 和 l 這樣的氨基酸的交替構(gòu)型也很容易形成 dkp，所以這里有一個問題，如果 dkp信息發(fā)生在二肽 onctc 的 c 末端，所以什么？結(jié)果將是天冬氨酸信息也被稱為肽厚度的副反應(yīng)這是眾所周知的，這是由于原子氮的親核性，它可以攻擊天冬氨酸側(cè)鏈上的羧酸酯基團(tuán)以形成這種天冬氨酸中間體，如果在該位點(diǎn)水解，則可以通過水或制劑激活 um 甘氨酸攻擊by waterit 可以 um 轉(zhuǎn)化為天冬氨酸s uh 受到制劑的攻擊，它會形成天冬氨酸天堂，分子量增加 m+67，如果這種攻擊發(fā)生在此處的 b 位點(diǎn)，它將形成異天冬氨酸或異天冬氨酸氣體制劑雜質(zhì)蘆筍作為畸形的一部分，可以被酸和堿催化及其累積形成只要引入天冬氨酸就可以一直發(fā)生它可以在肽合成配方和儲存的步驟中發(fā)生它還可以處理受保護(hù)的天冬氨酸并且保護(hù)基團(tuán)對肽組裝的天冬氨酸氣體炎癥具有非常顯著的影響s 高度序列依賴性因此第二個氨基酸甘氨酸或絲氨酸何時熨燙天冬酰胺天冬氨酸或它具有交替構(gòu)型，如天冬氨酸 d 氨基酸或天冬氨酸 l 氨基酸 增加阿斯巴甜形成的可能性谷氨酸也可以經(jīng)歷類似的反應(yīng)，但程度要小得多。這里需要強(qiáng)調(diào)的是，一些肽修飾，如側(cè)鏈到側(cè)鏈環(huán)化也可以誘導(dǎo)一些天冬氨酸天冬酰胺的形成，當(dāng)羧酸基團(tuán)在osbotic側(cè)鏈上被激活時，相應(yīng)的活性星形可以與氨基反應(yīng)形成目標(biāo)側(cè)鏈瞄準(zhǔn)環(huán)化但另一方面概率由于這些羧基的活化，天冬氨酸的含量也增加我形成這種天冬氨酸的變形首先是中間體，當(dāng)水解是在那里或這里發(fā)生，它會產(chǎn)生天冬氨酸或異天冬氨酸，這種反應(yīng)被認(rèn)為是肽類藥物最明顯的分解反應(yīng)，它可以在低 ph 值下進(jìn)行我的形成和它的高度序列依賴性作為蛋白質(zhì)甘氨酸天冬酰胺甘氨酸或灼熱節(jié)流組氨酸賴氨酸色氨酸天冬氨酸谷氨酸更容易應(yīng)用它'sa 溫度 鐵 熨斗 強(qiáng)度 溶劑和粘度依賴性 它可能會發(fā)生 肽厚度 純化 定位 配方和儲存 需要注意的是，天冬酰胺的側(cè)鏈也可以攻擊肽的主鏈以形成這種琥珀酰胺肽并導(dǎo)致肽的片段化，因此側(cè)的第二部分肽合成中的反應(yīng)是肽裂解和全球范圍內(nèi)的可悲反應(yīng)，第一個說積累一些氨基酸如 uh 色氨酸很容易被例如來自保護(hù)基團(tuán)的支流陽離子激活積累 orit'sa tfa 酯形成殘缺的色氨酸雜質(zhì) umcysteine 也容易被小管積聚以形成支流半胱氨酸 硫醇基團(tuán)和一些肽接頭樹脂接頭 如果它像額定功率或thering camera 樹脂或環(huán)形mbha 樹脂一樣明顯裂解被剪輯在連接體一側(cè)它可以產(chǎn)生不同類型的陽離子，這些包含可以使一些易感殘基上的烷基化，如色氨酸在這里它可以通過肽切割和全局保護(hù)的其他類型的細(xì)胞反應(yīng)產(chǎn)生不同的累積計(jì)算機(jī)，其中包括 202106 163 和 265 雜質(zhì)。例如可以通過 tfa 和 edt 對 m plus 72 的雜質(zhì)進(jìn)行修改，并且 edt 可以修改持續(xù)音以形成 m plus92 雜質(zhì)及其結(jié)構(gòu)和現(xiàn)有的 acm 保護(hù)基團(tuán)可以在像 theedt 這樣的掃描管理器存在下被 tfa 過早裂解并形成系統(tǒng)，并且可以通過 edt 進(jìn)一步修飾為相應(yīng)的雜質(zhì)，并且灼熱可以被精氨酸的 pbf 保護(hù)基團(tuán)修飾以形成磺化雜質(zhì)隨著 mplus80 分子量的增加，在肽裂解和全局保護(hù)過程中會發(fā)生氧化和還原，組胺色氨酸與持續(xù)的蛋氨酸會被氧化成相應(yīng)的氧化降解，例如色氨酸的二聚化也可能在氧化過程中發(fā)生，形成色氨酸氨基酸殘基的二聚體，這主要是芳香族的。 the terracinghastings 色氨酸 氟丙氨酸和丙酮酸在存在 t3 和醛的情況下，熨燙可能會發(fā)生變化，相應(yīng)的交替雜質(zhì)減少肽組裝體中的切割不是很顯著，但鐵人三項(xiàng)可以將諸如 trip fan 的氨基酸總和減少到相應(yīng)的降解，其中 n 加兩個分子量增量和甲基化或乙基化酪氨酸例如可以通過 uh 細(xì)胞苯甲醚進(jìn)行 d-甲基化-乙基化以形成這種相應(yīng)的梯田雜質(zhì)與 m 加上 14 分子量減少二硫化物可以通過 tfaum 實(shí)際上在 tfa 中通過硒到相應(yīng)的硫醇對現(xiàn)在我們來到我的第二部分介紹是關(guān)于肽的不穩(wěn)定性和當(dāng)然它的退化's 與肽厚度的副反應(yīng)交織在一起，但本部分我將重點(diǎn)關(guān)注肽分子的固有特性和主要在移液管配方中的降解和肽不穩(wěn)定性預(yù)測對于藥物非常關(guān)鍵，因?yàn)樗鼘τ谒幬锇l(fā)現(xiàn)和評估哪些潛在的候選藥物可能不穩(wěn)定非常有用。 api 可制造性評估以了解哪些制造過程可以降解肽有助于預(yù)測肽儲存的穩(wěn)定性并指導(dǎo)相應(yīng)分析方法的開發(fā)以檢測某些肽梯度s 對藥物產(chǎn)品的可制造性評估也非常有用，因此肽不穩(wěn)定性預(yù)測的第二部分分為六類肽水解肽重排循環(huán)片段化寵物肽肽加合物肽交聯(lián)和溶劑誘導(dǎo)肽降解肽水解在肽降解中非常常見第一部分是關(guān)于乙酰和急性肽水解這個小疾病很容易發(fā)生水解，就像加速的足球一樣，機(jī)制是它們可以形成這個 uh 五元環(huán)，5 羥基氧化鈉，并切斷 n 端氨基酸，從而截斷序列它通過完整的形成引發(fā)這樣的親核攻擊這五個記憶中間體和切割 aiband c 末端位點(diǎn)的肽，例如這個帶有甲基 aib 殘基的環(huán)狀肽s 在該位點(diǎn)通過 tfa 水解，將環(huán)肽切割成相應(yīng)的線性肽。第三類水解位于具有 n-甲基 xaa 的 c 端更容易發(fā)生酸中毒，例如這種模式是帶有然后-甲基 c-末端殘基和 m-此處的鍵被更多標(biāo)記為切割氨基酸以形成該吸管雜質(zhì) 其機(jī)制是 c 末端的羧酸酯基團(tuán)可以攻擊此處的 mi 鍵，因?yàn)樵撾逆I的優(yōu)勢構(gòu)象并形成這五種膜活性并重排為相應(yīng)的酸酐并被酸裂解為相應(yīng)的肽酸灼燒或周圍和肽的內(nèi)部序列也可以驅(qū)動水解，因?yàn)榱u基的核速度在這里它可以攻擊前面的移液器在該位點(diǎn)鍵合形成五種膜中間體，這些中間體重排成相應(yīng)的酯，這些酯在灼熱位點(diǎn)水解成肽，sink uh 還可以催化 Hasting 和灼熱序列的水解，以將肽鎖定成有利的構(gòu)象，促進(jìn)細(xì)胞環(huán)的親核攻擊形成這五個記憶中間體并切斷肽鍵從而形成水解天冬氨酸可以介導(dǎo)肽鍵水解asp pro是一個眾所周知的序列，因?yàn)樗哂懈咚嶂卸緝A向天冬氨酸和脯氨酸肽鍵可以在酸的存在下被切割形成天冬氨酸和proling片段，因?yàn)樗男蛄幸彩侨菀姿?，因?yàn)檫@里的氫鍵可以切斷側(cè)面的肽鍵蘆筍和血清以及天冬氨酸氣體可以攻擊酰胺鍵之前的酰胺鍵，形成六種膜中間體，這些中間體重排為酸酐并水解為兩部分。s 位于肽的 then 末端，以切斷該 hast pro 片段并形成雜質(zhì)，m 加上分子量中的二三四，組氨酸的 e 咪唑側(cè)鏈可能參與該過程，通過 dkp 切割 hispro 二肽并形成片段化肽當(dāng)天冬酰胺或異構(gòu)體位于肽的 c 末端時，它們易于水解形成相應(yīng)的酸離子，這可能是由于肽的側(cè)鏈和主鏈之間的氫鍵，并促進(jìn)水對原子化鍵的攻擊形成相應(yīng)的酸，另一種機(jī)制是羧酸酯末端可以攻擊結(jié)合在側(cè)鏈上的酰胺，形成琥珀酸酐，隨后水解生成相應(yīng)的天冬氨酸甲醇胺和羰酰胺非常容易水解，即使這種動機(jī)有時存在于某些肽分子艙中，是這種結(jié)構(gòu)嗎？同義的半氨基和甲醇酰胺是羰基結(jié)構(gòu)域的酰胺形式，碳結(jié)構(gòu)域很容易水解成相應(yīng)的胺和醛，或者它可以脫水到平均和內(nèi)閣的量，類似地它很容易水解產(chǎn)生相應(yīng)的酰胺，通過釋放醛烯酸和脫氫丙胺很容易水解這些是脫氫丙氨酸和烯酸的結(jié)構(gòu)嗎？ 依達(dá)米特可以水合成相應(yīng)的甲醇鹽，我們知道甲醇酰胺不穩(wěn)定，可以水解成交聯(lián)的離子和酮，這是脫氫丙氨酸水解的一個具體例子相應(yīng)的碘化物，這是帝國肽的下一個類別肽降解是重排，所以第一個例子是沒有遷移我們知道，由于細(xì)胞基團(tuán)可以在氨基和羥基之間遷移，例如當(dāng)我們在肽和末端有乙酰絲氨酸時，乙酰基可以在這兩個動機(jī)之間遷移取決于 osu 異構(gòu)體的 ph或n-?；悩?gòu)體所以要注意then-accept 加速系列的這些序列以及肽的深度當(dāng)它出現(xiàn)在氨基時乙?；梢詮膗h羥基遷移到氨基形成相應(yīng)的離子異構(gòu)體所以還要注意深度c肽軸承α氨基和絲氨酸可以被tfa修飾為相應(yīng)的tfa酯，此后，uh三氟乙?；部梢詮牧u基遷移到氨基形成那種不可逆的 umtfa 乙酰化雜質(zhì)，分子量增加 96 接下來我們將討論端到端的異遷移一些氨基酸，例如二氨基丙酸 dpr 簡稱 dab，即二氨基丁酸或其他容易發(fā)生這種重排的物質(zhì)，例如 dpr 容易適應(yīng)異遷移從主鏈到側(cè)鏈，而這五個膜中間體形成相應(yīng)的異構(gòu)體，一旦涉及到 dab，它具有兩種遷移概率：一個根 a 一個根 b 和根 a 它形成這種異構(gòu)體和根 b 它導(dǎo)致肽的片段化，這兩個遷移是非常危險，因?yàn)樗鼤a(chǎn)生異構(gòu)體，有時如果你不這樣做'沒有異構(gòu)體的參考這種遷移可以忽略您的檢測我們有這種經(jīng)驗(yàn)，有時當(dāng)您不這樣做時tmake 雜質(zhì)的參考，這種降解不會被檢測到，還有其他東西可以通過類似的降解途徑導(dǎo)致電子化，從而形成肽的碎片，我認(rèn)為大自然選擇許可而不是其他東西 b 和 dpr 有一些原因，這可能解釋了為什么賴氨酸被選中接下來我們談?wù)摱说蕉说你~水分遷移碳分子有時在肽藥物中，碳水分可以通過這種機(jī)制從一個電壓遷移到另一個電壓，形成銅摩爾遷移和芳族脲，例如如果中間基團(tuán)與芳族殘基相連，這種遷移是接下來我們更有可能發(fā)生將討論肽的消除，因此在較大位置上的吸電子取代例如這里是具有吸電子基團(tuán)的β位置，消除的可能性很高，這就是為什么我們稱之為β消除和β消除可以通過e1cb機(jī)制發(fā)生在基本條件下它形成脫水腺嘌呤和當(dāng)系統(tǒng)殘基具有一些保護(hù)基時，系統(tǒng)殘基上可能會發(fā)生相應(yīng)的加合物，因此在存在制劑的情況下，這種遷移率可能會被切斷并形成相應(yīng)的脫氫丙氨酸降解物，例如在肽的組裝中以及當(dāng)系統(tǒng)位于 c 末端時，它很容易發(fā)生β消除，形成相應(yīng)的和制備的物質(zhì)，然后可以通過微加成反應(yīng)形成相應(yīng)的制備雜質(zhì)，m加51。二硫化物也很容易發(fā)生β消除，這也是在堿基二硫化物存在的情況下發(fā)生β消除形成二氫丙氨酸和前硫化物和亞硫酸氫鹽可以被降解成持續(xù)和硫化，或者它可以被水解成相應(yīng)的硫酸，并且硫酸可以被歧化成比例二硫化物也容易發(fā)生β消除，這是在堿性二硫化物存在下的機(jī)理，它發(fā)生β消除形成二氫丙氨酸，預(yù)硫化物和亞硫酸鹽可以降解為持續(xù)和硫化物，或者它可以水解成相應(yīng)的硫酸，并且硫酸可以按比例歧化。二硫化物也容易發(fā)生β消除，這是在堿性二硫化物存在下的機(jī)理，它發(fā)生β消除形成二氫丙氨酸，預(yù)硫化物和亞硫酸鹽可以降解為持續(xù)和硫化物，或者它可以水解成相應(yīng)的硫酸，并且硫酸可以按比例歧化。被合成半胱氨酸和丁香酸二硫化物也可以進(jìn)行β消除，從而形成erasmic二硫化物三硫化物和致死性或單亞硫酸鹽二硫化物的兩個分子可以進(jìn)行二硫化物加擾，產(chǎn)生二聚體，二聚體可以進(jìn)一步進(jìn)行β消除，嗯，產(chǎn)生兩個動機(jī)，分別是脫氫丙氨酸和亞硫酸丙酯，以及預(yù)加的肽it可以進(jìn)行三硫化物形成以產(chǎn)生三硫化物，而其余為脫氫腺嘌呤它可以通過微量加成進(jìn)行填埋，或者脫氫可以進(jìn)行水解并形成相應(yīng)的丙酮酸肽并提供丙酮酸肽二硫化物肽也可以進(jìn)行更好的消除以形成脫氫丙氨酸和亞硫酸丙酯，這可以通過微量添加重新洗牌為二硫化物，但總體上會產(chǎn)生光柵化sso四二硫化物β消除可以產(chǎn)生的降解類型接下來我們將討論肽加合物的第一類加合物是加合物肽可以被甲醛修飾，相應(yīng)的中間體分子量m加30，這種衍生物可以進(jìn)一步脫水到m加12的相應(yīng)移位堿基。這些修飾發(fā)生在肽和末端，形成的鞘堿基可以環(huán)化為相應(yīng)的咪唑烷醛也 m 加 12。一些氨基酸，如半胱氨酸或色氨酸、天冬酰胺或組胺，也可以進(jìn)行不同類型的環(huán)化形成相應(yīng)的環(huán)化反應(yīng)，再加上 12 種雜質(zhì)，甲醛和甲酸的存在可以適應(yīng)伊索克拉克反應(yīng)，形成礦物基團(tuán)的積累，甚至是氨基的染料烷基化。接下來我們將討論關(guān)于肽飽和 肽飽和可以在乙酸乙酯存在下被乙酸催化形成相應(yīng)的乙酰化肽，組氨酸也可以催化乙?；覀冎肋溥蚴撬徇w移的良好催化劑，組氨酸可以催化這種反應(yīng)，首先形成加速組氨酸，細(xì)胞基團(tuán)可以從組氨酸遷移到相應(yīng)的氨基以產(chǎn)生加速's 雜質(zhì)我們知道，尿素有時可以是一種快速甚至快速降解的相應(yīng)坐骨酸，在羧酸酯基團(tuán)的過程中形成相應(yīng)的羧酸碳酸混合酸酐，一旦形成這種反衍生物，它可以修飾氨基并形成相應(yīng)的乙酰胺雜質(zhì)并釋放二二氧化碳銨加合物的類別是肽耦合調(diào)制，電容也可以由尿素觸發(fā)，尿液可以形成交叉鍵合等溫酸，它可以給氨基降解的頂體銨二氧化碳，一旦這些異音酸形成，它可以修飾多種肽，包括礦物基團(tuán)半胱氨酸、組氨酸和羧酸酯基團(tuán)和翼糖和精氨酸和磷酸形成相應(yīng)的carbomolation 雜質(zhì)接下來我們討論肽交聯(lián)形成二聚體或多聚體第一類是氨基轉(zhuǎn)移，我們知道氨基和 imi 之間可以發(fā)生轉(zhuǎn)化以形成轉(zhuǎn)化的酰亞胺和胺，如果這種轉(zhuǎn)化發(fā)生在兩個分子之間，一個分子比較含有氨基，另一個分子有相應(yīng)的羧基這種轉(zhuǎn)變會導(dǎo)致形成分子量是單體減17的兩倍的二聚體，因?yàn)檫酪粋€銨分子被踢出然后我們討論天冬酰胺誘導(dǎo)的交聯(lián)，天冬氨酸可以在含有天冬氨酸的肽上發(fā)生，一旦形成天冬酰胺，它也可能被攻擊來自另一個肽分子的氨基形成二聚體取決于攻擊途徑的肽雜質(zhì)也可以誘導(dǎo)交聯(lián)，如果天冬酰胺c-末端殘留物形成相應(yīng)的肉桂酸酐，它可以被來自其他分子的氨基攻擊形成二聚體，例如胰島素可以通過這種機(jī)制形成胰島素二聚體β消除也可以導(dǎo)致肽的交聯(lián)，例如，如果 β 消除是針對肽，它將形成相應(yīng)的脫氫基序，這可能會被另一個肽分子通過微吸附攻擊形成二聚體，我們表明脫氫可以與賴氨酸與組胺或與系統(tǒng)反應(yīng)在二硫化物中形成不同種類的直徑組合絕對是二硫化物交聯(lián)的熱點(diǎn)在微量線性持續(xù)肽雜質(zhì)的存在下降解形成二聚體，二聚體已經(jīng)交叉連接，但二聚體可以進(jìn)一步進(jìn)行雙消除并產(chǎn)生相應(yīng)的肽與半胱氨酸和亞硫酸氫鹽，這可以進(jìn)一步進(jìn)行一些分子間交聯(lián)以產(chǎn)生不同類型的交聯(lián)得到這些加合物的中間體，通過相應(yīng)的烯胺進(jìn)一步脫水，分子量增加40。丙酮也可以與n-末端氨基反應(yīng)形成免疫鹽的中間體，它可以在分子內(nèi)進(jìn)行環(huán)化形成免疫二唑烷醇它還具有完全的分子量增加所以這就是我今天的所有演講，非常感謝您的關(guān)注