C15H31CO

C15H31CO is the acyl group derived from palmitic acid (hexadecanoic acid). In chemical shorthand it is written as R-CO-, with R representing the hexadecyl (C15H31) part. The acyl fragment has the formula C16H31O when counted as a standalone moiety. The term palmitoyl (or hexadecanoyl) is the common name for this fragment.

In biochemistry, the palmitoyl group plays a key role in lipid modification of proteins. It is transferred from palmitoyl-CoA to target residues, most notably cysteine, via thioester bonds in a process known as S-palmitoylation. This modification increases hydrophobicity and promotes association of proteins with cellular membranes, influencing localization, stability, and signaling. Palmitoylation is dynamic and reversible, allowing rapid regulation of protein function.

In organic synthesis, the palmitoyl group is used as a hydrophobic acyl substituent in the formation of esters and amides. Palmitoyl derivatives are common in lipid chemistry and materials science. A related reagent, palmitoyl chloride (C16H31OCl), is a reactive derivative used to introduce the palmitoyl group into alcohols or amines. The palmitoyl moiety is a characteristic 16-carbon saturated chain (C16) that confers distinct physical properties to the compounds in which it appears.

See also: palmitic acid; hexadecanoic acid; palmitoyl-CoA; palmitoylation.