Fundamentals of Molecular Biology - V.I. Rezyapkin 2009

Regulation of Gene Expression
Post-Translational Protein Modification

Upon completion of Translation, the protein molecule may undergo various alterations known as post-translational modifications.

As a result of post-translational modifications, various chemical groups can be attached to amino acid residues within protein molecules, such as phosphate, acetyl, methyl, carboxyl, and poly(ADP-ribose) groups, among others. Amino acid residues may undergo glycosylation (attachment of a carbohydrate component), hydroxylation—whereby Proline is converted into 4-hydroxyproline and Lysine into 5-hydroxylysine—iodination (during The formation of THYROID Hormones), and more. Lipoproteins are formed as a result of the post-translational attachment of a lipid component to a protein. Post-translational modifications can also occur via the Cleavage of polypeptide chain fragments to yield functionally active Proteins.

Post-translational modifications are typically catalyzed by specific Enzymes. At the same time, certain intramolecular rearrangements of proteins take place without the involvement of enzymes.

Post-translational modifications are involved in establishing the three-dimensional Structure of protein molecules, regulate their activity, determine their cellular localization, and give rise to a multitude of protein forms.



Last update: 12/08/2026

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