Polypeptide chain breakage

Haskill, J. S., and Hunt, J. W., 1967a, Radiation damage to crystalline ribonuclease Identification of polypeptide chain breakage in the denatured and aggr ated products. Radial Res. 32 827-848. 

Generally, protein denaturation includes the complete or partial unfolding of the polypeptide chain, cleavage of disulfide linkages, and breakage of noncovalent interactions. Denaturation is sometimes reversible. The reversing process is called renaturation. 

Denaturation is a process, or a succession of processes, in which the steric arrangement of polypeptidic chains inside the native protein molecule is changed, and simultaneously the original properties of the protein molecule are changed to those of the denatured protein. Denaturation is any modification of the secondary, tertiary, or quartary structure of the protein molecule, excluding any breakage of a covalent bond (39). 

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