GO:0006464

cellular protein modification process

Details: 
The covalent alteration of one or more amino acids occurring in proteins, peptides and nascent polypeptides (co-translational, post-translational modifications) occurring at the level of an individual cell. Includes the modification of charged tRNAs that are destined to occur in a protein (pre-translation modification). [GOC:go_curators]
Evidence Code: