AMP deaminase (AMPD) is an allosteric enzyme involved in the regulation of adenosine metabolism. It catalyzes a central reaction in purine nucleotide biosynthesis where AMP is deaminated to IMP liberating ammonia. There are three functional isoforms of AMPD. AMPD1 (E.C. No 3.5.4.6.) is the skeletal muscle-specific isoform M located in type II muscle fibers, neuromuscular junctions and in capillaries. This protein is the predominant member of AMPD multi-gene family and is considered as the sensor of the cell's changing energy requirements. AMPD1 deficiency causes irregular muscle metabolism due to lower rate of ATP degradation, phosphocreatine hydrolysis and accumulation of lactic acid. Mutated AMPD1 expression has been detected in neuromuscular disorders, exercise-induced skeletal muscle myopathies and congestive heart failures due to coronary artery diseases.