Protein Chemistry. Structure, Properties, Research Methods - Shendryk A.N. 2022

Protein Structure
Protein Structure
Chemical Fragmentation

In addition to the Enzymatic Cleavage of protein molecules, Chemical Fragmentation is also employed. For this purpose, chemical Reagents are used that are capable of specifically interacting with individual Amino Acids within Peptides, resulting in the Cleavage of the corresponding peptide bond.

Such fragmentation is carried out:

1. at Methionine residues using Cyanogen bromide (BrCN);

2. at Tryptophan residues using N-Bromosuccinimide (NBS);

3. at tryptophan residues using a mixture of dimethyl sulfoxide (DMSO) and a hydrogen halide (HGal);

4. at tryptophan residues using cyanogen bromide in heptafluorobutyric acid;

5. at tryptophan residues using o-iodosobenzoic acid;

6. at Tyrosine residues using N-bromosuccinimide;

7. at the Asn-Gly bond using hydroxylamine;

8. at the Asp-Pro bond via Partial Acid Hydrolysis.

Methionine and tryptophan are relatively rare amino acids; therefore, following Specific Cleavage at their respective positions within protein peptide chains, relatively large fragments are formed (40–80 residues). Cleavage according to items 7 and 8 yields even larger fragments.