Following chemical synthesis of peptides by solid-phase Fmoc, there are many methods of cleavage, and two basic types are now introduced that we commonly use.
1. Strong acid method (TFA)
The dry resin was placed into a shake flask and an appropriate amount of scavengers containing was added. (Scavengers) Trifluoroacetic acid cutting reagent (TFA), 10-25ml/g resin, capped and shaken intermittently at room temperature with rotation. The resin was drained, washed 2-3 times with new TFA, the filtrate was combined, and 8-10 times the volume of ice diethyl ether was dropped. Sometimes, some TFA can be steamed to obtain crude peptide precipitates. Ether can be used to increase precipitation efficiency by ice-assisted cooling. Finally, the precipitated crude peptide product was collected.
Suitable resin: Wang resin or Rink Amide resin
2, Weak acid method (TFA or acetic acid dilution)1% TFA:
1g of resin containing peptides was added to a glass shake flask of dichloromethane solution containing 1%TFA, sealed and shaken for 2 min. The filtrate was pressed with nitrogen into another new methanol shake flask containing 10% pyridine, and the procedure was repeated 10 times. The protective peptides remaining on the resin were washed three times using 30ml of DCM and 30ml of MeOH. Residues were checked and cleaned by TLC or HPLC. All filtrates were combined and 5% of the solvent was cooked under reduced pressure. Forty ml of water was added and precipitation assisted with the cooling mixture. After filtration, the product was washed three times with clean water, placed in a vacuum drying oven, and dried with KOH or P2O5.
Dilute acetic acid:
Peptides hung on the resin were treated with cutting solution for 2 h using AcOH//TFE/DCM (2:2:6), the resin was filtered, and the resin was washed three times with cutting solution. The excess acetic acid was removed by adding 15-fold n-hexane to the mixed filtrate and rotary steeping.
Application resin: 2-CTC resin
Post time: May-28-2025