has_participant has participant cellular protein modification process protein tagging activity biological_process GO:0006464 protein modification process process resulting in protein modification 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). protein modification process cellular protein metabolic process tyrosine-protein kinase ABL1 (human) tyrosine-protein kinase Yes (human) muscarinic acetylcholine receptor M1 (human) muscarinic acetylcholine receptor M3 (human) tyrosine-protein kinase ABL2 (human) protein-arginine deiminase type-4 (human)