Rapid electrophoretic determination of neuron-specific enolase isoenzymes in serum

This assay procedure for each of the two neuron-specific enolases (alpha gamma and gamma gamma) and the non-neuronal enolase (alpha alpha) in serum involves two steps: electrophoretic separation of the three isoenzymes--alpha alpha, alpha gamma, and gamma gamma--on cellulose acetate, and bioluminescence measurement of total enolase activity. From these data, the activity concentrations (U/L) of the three isoenzymes in serum are calculated. Both measurement steps are based on the enzymatic activity of enolase and thus differ from the immunological methods currently in use, which require the availability of specific antibodies. The method is rapid (approximately 30 min for both steps) and requires only 10 microL of serum for the complete analysis. Studies of normal children and adults, and of patients suffering from neuroblastoma and small-cell lung cancer, show that it is suitable for clinical use. Furthermore, the fact that both neuron-specific isoenzymes of enolase can be systematically separated is an advantage over immunological techniques in determining isoenzyme patterns for pathological samples.