Amino Acids, Peptides and Proteins - Dévényi T., Gergely J. 1976

Hydrolysis of Proteins and Peptides
Cyanogen bromide cleavage of proteins

Principle of the method. In an acidic medium, Cyanogen bromide specifically cleaves polypeptide chains of Proteins at Methionine residues to form homoserine lactone (iodoacetamide reacts with proteins similarly to cyanogen bromide). The reaction proceeds According to the following scheme:

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Scope of application. Cleavage of proteins into relatively large Polypeptides for their structural analysis.

PROCEDURE    

The protein under study is dissolved or suspended in 0.1 N HCl, a 30-fold excess of cyanogen bromide is added, the mixture is incubated in a fume hood with stirring for 24 h, and then the reaction mixture is lyophilized.

NOTE

For a successful analysis, it is highly important to choose an appropriate method for the fractionation and purification of the large polypeptide fragments resulting from the action of cyanogen bromide on the protein. Initially, it is convenient to perform preliminary size-exclusion fractionation using Gel filtration, followed by Ion-exchange Chromatography on a DEAE- or CM-Cellulose Column, preferably in the presence of urea.

Recommended Literature

Boyer Р. D., The Enzymes, Vol. Ill, Academic Press, New York, London, 1971.

Colowick S. P., Kaplan N. О., eds., Methods in Enzymology, Vol. XXV, Academic Press, New York, London, 1972.

Hill R. L., Adv. Protein Chem., 20, 37 (1965).

Kasper С. B., in: Needleman S. P. ed., Protein Sequence Determination, p. 137—165, Springer Verlag, Berlin—Heidelberg, New York, 1970.

Witkop В., Adv. Protein Chem., 16, 221 (1961).