propionylated

Propionylated refers to a molecule that has been modified by the addition of a propionyl group, derived from propionic acid, to a nucleophilic site such as an amine or hydroxyl group. In organic synthesis, propionylation is a form of acylation that yields propionamide or propionate derivatives, depending on whether the target is an amine or an alcohol. The propionyl group is introduced via reagents such as propionyl chloride, propionic anhydride, or mixed anhydrides, typically in the presence of a base and an appropriate solvent. The result is an amide linkage (R-NH-CO-CH2-CH3) or an ester linkage (R-O-CO-CH2-CH3).

In biochemistry and molecular biology, propionylation also describes a post-translational modification in which a propionyl group is transferred to proteins, most commonly on lysine residues, forming N6-propionyllysine, or at N-termini. Propionyl-CoA serves as a cellular donor of the propionyl group, linking metabolism to protein modification. Propionylation is related to other acylations such as acetylation and malonylation and is detected by mass spectrometry and antibody-based methods. It is studied for potential roles in gene regulation, chromatin structure, and metabolic signaling.

In proteomics and sample preparation, chemical propionylation is used to block free amino groups, particularly the ε-amino groups of lysines, before proteolytic digestion, often with trypsin. This allows more uniform peptide generation and simplified MS analysis, especially for histone and chromatin studies, where multiple lysine residues may carry other modifications.

Safety and handling of propionylating reagents follow standard chemical hygiene practices, as reagents such as propionic anhydride and propionyl chloride are corrosive and reactive. See also acetylation, malonylation, and propionyl-CoA.