Alpha-enolase, also known as Enolase 1, is one of three enolase isoenzymes and a glycolytic enzyme expressed in most tissues. This protein plays a key role in anaerobic metabolism under hypoxic conditions and may act as a cell surface plasminogen receptor during tissue invasion. Abnormal expression of alpha-enolase is associated with tumor progression in some cases of breast and lung cancer. It also has been identified as an autoantigen associated with Hashimoto's encephalopathy and severe asthma.