An ultramicro bioluminescence assay of enolase: application to human cerebrospinal fluid.

A highly sensitive method based on bioluminescence is described for the assay of enolase which can measure as little as 0.4 X 10(-6) IU of activity. This corresponds to an amount of enzyme present in 1-2 microliters of normal human cerebrospinal fluid and is therefore easily applicable to clinical samples of CSF which can only be obtained in very small amounts. The reproducibility of the method is very high within a broad range of enzyme concentrations and the assay is linear from 0.4 X 10(-6) IU up to at least 50 X 10(-6) IU of enzyme. This would permit application of the method to biological samples containing low as well as high enolase activities and especially for monitoring changes in enolase concentrations in the CSF and in the serum, as a function of pathological lesions in the central nervous system and other tissues.