Post-translational modifications of amino acids include all the following EXCEPT which one?
A) disulfide bond formation
B) removal of methionine
C) protease cleavage
D) capping by 7-methylguanidine
E) attachment of prosthetic groups

Question

Quizplus · Accepted Answer

All of the options except for D are examples of post-translational modifications of amino acids. Disulfide bond formation involves the covalent bonding of two cysteine residues, while removal of methionine is a common processing step for proteins synthesized with methionine as the first amino acid. Protease cleavage involves the cleaving of peptide bonds within the protein sequence. Attachment of prosthetic groups involves covalent attachment of non-protein molecules to amino acid residues in a protein. Capping by 7-methylguanidine is not a known post-translational modification of amino acids.

Post-Translational Modifications of Amino Acids Include All the Following EXCEPT