Brain-specific proteins: solid-phase immunobioluminescence assay for neuron-specific enolase in human plasma

Area of Science:

• Biochemistry
• Immunology
• Enzymology

Background:

• Enolase (EC 4.2.1.11) exists as different isoenzymes, including alpha alpha- and gamma gamma-forms, primarily found in human brain.
• Accurate quantification of these isoenzymes in biological samples is crucial for diagnostic purposes, particularly in oncology.

Purpose of the Study:

• To develop and validate a highly specific immunoassay for quantifying alpha alpha- and gamma gamma-enolase isoenzymes in human plasma.
• To assess the utility of this assay in measuring enolase isoenzyme activities in patients with malignant tumors.

Main Methods:

• Generation of specific rabbit antibodies against purified human brain alpha alpha- and gamma gamma-enolase isoenzymes.
• Immunoabsorption and desorption of antibodies, followed by coating onto polystyrene tubes for assay development.
• Quantification of enolase isoenzyme activity using a firefly luciferase bioluminescence system to measure ATP accumulation.

Main Results:

• The developed immunoassay demonstrated high specificity, directly correlating with the antibodies used for coating.
• The assay achieved a low detection limit of approximately 5 X 10(-9) U (0.1 pg or 10(-18) mol of enzyme protein).
• The assay allowed for separate, rapid, and precise evaluation of enolase isoenzyme activities in human plasma.

Conclusions:

• A novel, highly sensitive, and specific immunoassay for human enolase isoenzymes has been successfully developed.
• This assay is suitable for the precise measurement of enolase isoenzyme activities in human plasma.
• The assay holds potential for application in the diagnosis and monitoring of malignant tumors by analyzing plasma enolase isoenzyme profiles.