A simple and convenient method for the purification of neuron specific enolase (NSE)from human brain is described through only one DEAE-Sephadex A50 chromatography.The specific activity is 92.1U/mg and increase of purity 59.4 fold.Certain biophysical and biochemical features were also studied.The molecular weight of the subunit of NSE is 45 000 and pI is 4.7.Amino acid composition analysis showed that NSE is an acidic protein.