nonacylated

Nonacylated is an adjective used in chemistry and biochemistry to describe molecules, compounds, or biomolecules that lack an acyl group. An acyl group is a functional group derived from an organic acid by removal of a hydroxyl group, typically represented as R-CO–. Acylation is a common modification in biology, including the attachment of fatty acyl chains to lipids and proteins, for example N-myristoylation, palmitoylation, or acetylation. A nonacylated molecule therefore has no such covalent attachment at the sites where acylation would occur.

In proteins, nonacylated forms may be soluble and cytosolic, whereas acylation can promote membrane association, localization to organelles, or altered activity. Nonacylated states can be constitutive or result from enzymatic removal of acyl groups (desacylation) or inhibition of acyltransferases. The balance between acylated and nonacylated forms can influence function, signaling, and interactions with other biomolecules.

In physiology, desacyl ghrelin is a well-known nonacylated form of ghrelin that lacks the octanoyl modification and has distinct biological activity from the acylated form. In chemistry and lipid biology, nonacylated compounds are those without fatty acid or other acyl substituents, which can influence properties such as reactivity, solubility, and metabolic fate.

Measurement of acylation status typically involves mass spectrometry, chromatography, or specific antibodies. The term nonacylated is used relative to the presence of an acyl group, and its precise meaning can vary by scientific context.