Practical Protein Chemistry - A. Darbre 1989

Polypeptide Fragmentation by Chemical Methods
Cleavage at Methionine Residues
Other Reagents

Peptides can be cleaved at Methionine residues using agents that alkylate the thioether group via a reaction mechanism similar to Cyanogen bromide Cleavage. Iodoacetamide has proven to be the most effective reagent [109, 110]. Treating apocatalase with ethylenimine results in an addition reaction at the methionine thioether group, yielding an aminoethylsulfonium salt followed by peptide bond cleavage [166]. Combined with diagonal Electrophoresis, this reaction has been used to identify and isolate peptides containing methionine residues [187, 188].

Model peptides have demonstrated that methionine cleavage proceeds in high yield under the action of hydrogen fluoride [112, 133]. The reaction is accompanied by N→O-acyl migration at Serine and Threonine residues (Sec. 2.3.2). Because of this side reaction, the HF-mediated cleavage method is not used in Protein Chemistry.



Last update: 06/08/2026

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