“Odorless” TIS Cleavage Cocktail (Reagent B)

“Odorless” TIS Cleavage Cocktail (Reagent B)

 In place of highly odorous ethane dithiol and thioanisole, triisopropylsilane is used in Reagent B to scavenge cationic species. Reagent B is especially useful when the resin-product contains trityl-based protecting groups. Reagent B will not prevent oxidation of methionine residues during cleavage.

Composition of Reagent B

trifluoroacetic acid (88% v/v)

phenol (5% v/v)

water (5% v/v)

triisopropylsilane (2% v/v)

Use immediately after preparation Cleavage with Reagent B

1. If necessary, remove any Fmoc-protecting groups using the standard Fmoc deprotection procedure.

2. Wash the resin with dichloromethane.

3. Suspend the resin in Reagent B (100 µL/mg of peptide resin)

4. Stir the mixture for 1 hour at room temperature.

5. Filter and wash the resin with a little additional Reagent B.

6. Cool the combined filtrates to 4°C and add cold methyl t-butyl ether (3 times the volume of the combined filtrates) to precipitate the crude peptide.