Dissolution ntawm polypeptides
Txhua cov amino acid muaj cov khoom siv tshuaj lom neeg thiab cov solubility ntawm peptide nyob ntawm nws cov kab ke thiab kev hloov kho. Peb pom zoo kom noj ib qho me me ntawm peptide rau kev soj ntsuam solubility ua ntej dissolving tag nrho cov peptides.
Dissolving peptides yog ib kauj ruam tseem ceeb heev. Solubilization tsis raug yuav ua rau peptide poob lossis kev sim tsis ua haujlwm. Kev solubility ntawm peptides feem ntau yog nyob ntawm qhov sib lawv liag ntawm peptide, yog li ua tib zoo saib thaum tsim peptide. Nws raug pom zoo tias peptide ib ntus yuav tsum muaj 20% cov seem seem kom nws cov solubility.
Ua ntej siv, cov neeg siv khoom tuaj yeem ua raws li peb lub hauv paus ntsiab lus hauv qab no los xaiv cov kuab tshuaj uas tsim nyog rau yaj peptide.
Ua ntej, cov kuab tshuaj uas tau xaiv yuav tsum muaj peev xwm ua kom tiav cov peptide; Qhov thib ob, cov kuab tshuaj uas tau xaiv yuav tsum sib haum nrog cov kev sim; Thaum kawg, cov kuab tshuaj uas tau xaiv yuav tsum tsis txhob hnov qab lossis degrade peptide.
Ntev npaum li qhov peptide tso cai, koj tuaj yeem ua ntej yaj ib feem me me ntawm peptide thiab tom qab ntawd yaj tag nrho cov qauv. Yog tias koj xav tau rov qab peptide los ntawm cov kuab tshuaj, koj tuaj yeem xaiv cov kuab tshuaj thawj zaug uas ua rau nws yooj yim tshem tawm tom qab lyophilization.
Cov lus qhia hauv qab no tuaj yeem pab koj yaj peptides:
Peptides nrog tsawg dua 5 amino acids feem ntau yog soluble hauv aqueous daws, thiab muaj zog hydrophobic amino acids (W, I, L, F, M, V, Y) tshwj tsis yog.
If the charged amino acids are evenly distributed throughout the sequence, then contains >25% Cov amino acids (E, D, K, R, H) ntawm hydrophilic peptides thiab muaj<25%Peptides with hydrophobic amino acids are generally soluble in aqueous solutions. The purification system for peptides is generally 0.1% TFA/Water and 0.1% TFA/ ACN. Therefore, if the peptide is dissolved in a buffer with no or very weak buffering capacity, the result may be an acidic peptide solution. When using other methods to dissolve peptides, be sure to use a solvent that is pH The value is nearly neutral. acidic peptide (E+D The number of residues is more than K+R+H number of residues) and basic peptides (K+R+H The number of residues is more than E+D number of residues) in neutral pH value conditions than in acidic pH value is easier to dissolve.
For hydrophobic amino acid content is 50% ～75%peptide, even if the sequence contains >25% Charged amino acids kuj yuav insoluble los yog ib nrab soluble nyob rau hauv dej. Nws yog qhov zoo tshaj rau thawj zaug yaj cov peptide hauv qhov tsawg kawg nkaus ntawm cov organic hnyav xws li DMF, ACN, Isopropyl cawv, ethanol, acetic acid, 4-8 M GdnHCl, urea, los yog DMSO (tsis yog nyob rau hauv sequence C, W, M), thiab lwm yam organic solvents. Nws yog qhov zoo tshaj plaws los maj mam ntxiv cov organic hnyav uas yaj cov peptide rau hauv cov kua dej los ntawm kev poob. Yog hais tias cov tshuaj ua turbid, tej zaum nws yuav tau mus txog lub solubility txwv thiab tsis muaj siv nyob rau hauv txuas ntxiv mus dissolve nws. Nws yuav tsum tau muab sau tseg tias cov kuab tshuaj thawj zaug xaiv yuav tsum tau sib xws nrog kev sim system.
Hydrophobic amino acid content >75% Muaj zog hydrophobic peptides feem ntau kuj insoluble hauv aqueous daws. Xws li peptides kuj yuav tsum tau kho ua ntej nrog cov kuab tshuaj muaj zog (xws li TFA, Formic acid) yaj thiab kuj tuaj yeem ua rau nag lossis daus yog ntxiv rau cov tshuaj aqueous. Cov tshuaj peptide zaum kawg yuav xav tau ntau cov kuab tshuaj organic rau denature nws, thiab cov kuab tshuaj organic feem ntau tsis siv rau kev tshawb fawb txog kev ua haujlwm lom neeg hauv cov hlwb.
S, T, E, D, K, R, H, N, Q, Y High content (>75%) Polypeptide sequences zoo li tsim cov kev sib txuas ntawm cov khoom siv hluav taws xob tsis sib xws thiab yooj yim tsim cov gels hauv cov ntsiab lus aqueous. Xws li peptides tuaj yeem solubilized raws li tau piav qhia hauv kauj ruam 3. Yuav kom txo tau cov teeb meem tshwm sim thaum lub sijhawm tawg, nws raug nquahu kom cov neeg siv khoom siv ntau dua rau kev tsim thiab ua raws li cov txheej txheem los txhim kho cov solubility ntawm peptide.