Practical Protein Chemistry - A. Darbre 1989

Enzymatic fragmentation of the polypeptide chain
Methods for protein modification
Modification of protein carboxyl groups

Modification of carboxyl groups in short Peptides is carried out using a Water-soluble carbodiimide via Condensation with the corresponding diamines (1,2-diaminoethane or diaminomethane). With an appropriate choice of diamine, aspartic acid residues are converted into a Lysine analogue [112]. The condensation reaction of the peptide with 2 M diamine is carried out at pH 4.75 in the presence of 0.4 M 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride at 20 °C for 1 h. Then, a second portion of carbodiimide is added and incubated for an additional 5 h. The modified peptides are separated from reaction products and excess Reagents by Gel filtration. As a result, irreversible modification of all protein carboxyl groups occurs. The potential for using this type of reaction to modify high-molecular-weight Proteins has not been investigated. The 29-membered peptide Glucagon was modified in this manner; this is the largest peptide subjected to such modification.



Last update: 06/08/2026

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