myristoyl

Myristoyl is the acyl substituent derived from myristic acid, a saturated 14-carbon fatty acid. In biochemistry, the term describes the 14-carbon fatty acyl chain when it is covalently attached to other molecules. The most common context is attachment to proteins or lipids through covalent bonds.

In proteins, the prevalent modification is N-myristoylation, in which the myristoyl group is linked via an amide bond to the N-terminal glycine residue. This reaction is typically co-translational and uses myristoyl-CoA as the acyl donor, supplied by cellular acyl-CoA synthetases after activation of myristic acid.

The myristoyl group promotes membrane association and can regulate protein localization, interactions, and signaling. Myristoylation is relatively stable but can influence conformational changes and exposure of other lipid modifications such as palmitoylation in some proteins. The modification is essential for certain viral and cellular proteins; for example, the HIV-1 Gag polyprotein is N-myristoylated, which affects particle assembly.

Myristoyl-CoA and related derivatives participate in lipid metabolism and are present across eukaryotes. Dietary myristic acid can contribute to cellular pools via activation to myristoyl-CoA. The term "myristoyl" also appears in descriptors of myristoylated lipids and synthetic probes used to study membrane interactions and protein targeting.

In research and pharmacology, enzymes that catalyze N-myristoylation, notably N-myristoyltransferases, are studied as potential drug targets for parasitic diseases and cancer. The myristoyl group thus serves both structural and regulatory roles in biology and medicine.