adenylylate

Adenylylate is the verb form describing the enzymatic transfer of an adenylyl (AMP) group to a substrate, producing an adenylylated product. The process is commonly referred to as adenylylation or AMPylation, and its noun form adenylylation is often used interchangeably with adenylation in the biochemical literature. Enzymes that catalyze this modification are known as adenylyltransferases, which typically use ATP as the donor of the adenylyl group and release pyrophosphate as a byproduct.

Adenylylation can modify a range of substrates, including proteins, nucleic acids, and small molecules. In proteins, AMP transfer can alter activity, interactions, localization, or stability, effectively acting as a post-translational regulatory mechanism. In bacteria, a well-studied example is the adenylylation and deadenylylation of glutamine synthetase (GS) by adenylyltransferase (GlnE), which responds to nitrogen availability by toggling GS activity to regulate ammonium assimilation.

In recent years, AMPylation has been recognized as a broader signaling modification in eukaryotes and bacteria. Fic-domain enzymes are a prominent family that catalyze protein AMPylation, affecting signaling proteins such as GTPases and other targets during host–pathogen interactions. The modification can be reversible in some systems, allowing dynamic control of substrate function.

Adenylylate thus describes a chemical modification that attaches AMP to a substrate, a mechanism of regulation found across diverse life forms and contexts, distinct from, yet related to, other adenosine-containing modifications and to signaling pathways that generate cyclic AMP from ATP.