Protein Posttranslational Modifications: Roles in Aging and Age-Related Disease

Scheme 1

Two categories of posttranslational modifications of proteins: (1) covalent modification of a nucleophilic amino acid side chain by an electrophilic fragment of a cosubstrate and (2) cleavage of a protein backbone at a specific peptide bond. Reproduced with permission from Walsh et al. [20].