Low Odor Cleavage Cocktail (Reagent L)

Low Odor Cleavage Cocktail (Reagent L)

 In this cleavage cocktail, dithiothreitol (DTT) and triisopropylsilane replace the pungent scavengers ethanedithiol (EDT) and thioanisole. Additionally, unlike EDT, DTT does not react readily with the benzophenone moiety of 4-benzoylphenylalanine (Bpa), making Reagent L a preferred cleavage cocktail for Bpa-containing peptides.

Preparation of Reagent L

Combine trifluoroacetic acid (TFA, 88% v/v), triisopropylsilane (TIS, 2% v/v), dithiothreitol (5% w/v), and water (5% w/w). Use immediately.

Cleavage and Deprotection with Reagent L

1. Suspend the resin in Reagent L (5 – 10 mL/g resin). 

2. Allow the mixture to stand at room temperature for 90 minutes. 

3. Filter the resin. 

4. Wash the resin with TFA (5 – 10 mL/g resin). 

5. Combine the filtrates and add cold ether to precipitate the crude peptide.