Human Neuron specific enolase (NSE) (EC 4. 2. 1. 11) is a 47,138 dalton protein (434 amino acids) expressed in neurons of the peripheral nervous system (PNS) and central nervous system (CNS). NSE catalyzes the conversion of 2-phospho-Dglycerate into phosphoenol pyruvate, and is an essential enzyme in energy metabolism in nervous tissues. NSE corresponds to ENO2 or enolase gamma and is heavily expressed in neuronal cells, developing neuronal lineage and neuroendocrine cells. Release of NSE from damaged neurons into CSF and blood has also been used as a biomarker of neuronal injury.