Beta-enolase, also known as ENO3, is one of the three enolase isoenzymes found in mammals. This isoenzyme, a homodimer, is found in skeletal muscle cells in the adult. ENO3 play a role in converting phosphoglyceric acid to phosphenolpyruvic acid in the glycolytic pathway. Mutations in its gene can be associated with metabolic myopathies that may result from decreased stability of the enzyme.