Adenosine monophosphate (AMP), also known as 5'-adenylic acid, is a nucleotide. AMP consists of a phosphate group, the sugar ribose, and the nucleobase adenine. It is an ester of phosphoric acid and the nucleoside adenosine. As a substituent it takes the form of the prefix adenylyl-.

AMP plays an important role in many cellular metabolic processes, being interconverted to adenosine triphosphate (ATP) and adenosine diphosphate (ADP), as well as allosterically activating enzymes such as myophosphorylase-b. AMP is also a component in the synthesis of RNA. AMP is present in all known forms of life.

AMP does not have the high energy phosphoanhydride bond associated with ADP and ATP. AMP can be produced from ADP by the myokinase (adenylate kinase) reaction when the ATP reservoir in the cell is low:

Or AMP may be produced by the hydrolysis of one high energy phosphate bond of ADP:

AMP can also be formed by hydrolysis of ATP into AMP and pyrophosphate:

When RNA is broken down by living systems, nucleoside monophosphates, including adenosine monophosphate, are formed.

AMP can be regenerated to ATP as follows:

AMP can be converted into inosine monophosphate by the enzyme myoadenylate deaminase, freeing an ammonia group.