Enolase 2 (2-phospho-D-glycerate hydrolyase; also Neuron-specific Enolase, NSE, neural enolase and gamma-enolase) is a 46 kDa member of the Enolase family of enzymes. It is expressed in developing neurons and glia, is known to catalyze the generation of phosphoenolpyruvate, and is suggested to possess neurotrophic activity for neurons, likely through an extracellular mechanism. Human Enolase 2 is 434 amino acids (aa) in length. The enzymatic site spans most of the length of the molecule. Enolase 2 exists as both a noncovalently-linked homodimer, or heterodimer with alpha-enolase. Full-length human Enolase 2 shares 99% aa identity with both mouse and canine Enolase 2. It shares 83% aa identity with human enolases 1 and 3.