5aminoimidazole4carboxamide

5-aminoimidazole-4-carboxamide (commonly abbreviated AICA) is a small heterocyclic organic compound composed of an imidazole ring bearing an amino group at the 5-position and a carboxamide substituent at the 4-position. It is best known as a structural component and intermediate in purine nucleotide biosynthesis and as the aglycone of biologically active ribonucleotide derivatives.

In cellular metabolism AICA appears as part of the de novo purine synthesis pathway; its ribonucleotide and riboside forms (often referred to collectively by the acronym AICAR) are important metabolic intermediates. The phosphorylated ribonucleotide analogue ZMP (AICAR monophosphate) mimics AMP and can activate AMP-activated protein kinase (AMPK) in experimental systems, producing broad effects on cellular energy homeostasis, glucose uptake, and lipid metabolism.

Because of its relationship to AMPK signaling, AICA derivatives have been widely used in laboratory research to probe metabolic regulation, investigate cardioprotective and neuroprotective mechanisms, and model aspects of metabolic disease. Pharmacological and experimental use is typically limited to its riboside or nucleotide forms rather than the free base. AICA and its derivatives are produced synthetically for research and can also arise transiently in biological systems during nucleotide turnover.

Physicochemical properties, synthetic routes, and safety profiles vary with the specific derivative and salt forms; researchers handle such compounds according to standard laboratory safety practices. AICA itself is of interest mainly for its role as a scaffold in nucleotide chemistry and for the biological activities of its phosphorylated and glycosylated derivatives.