CHARACTERIZATION OF HUMAN LUNG ELASTIN-DERIVED PEPTIDES

The enzymatic breakdown of human lung elastin by leukocyte elastase pr ecedes the development of pulmonary emphysema, and releases elastin-de rived peptides (EDPs) into the circulation. While raised levels of EDP s measured by enzyme-linked immunosorbent assay (ELISA) have been prop osed as a possible marker for early detection of emphysema, average no rmal values of EDPs measured by different investigators have differed by up to a factor of 1000. Standardisation of the methodology for elas tin purification and EDP production in vitro is required to ensure the accuracy of EDP measurements in vivo, because antiserum used in the E LISA is raised against the EDPs produced in vitro. In the present stud y elastin was purified from human lung by sequential biochemical extra ction, and solubilised by leukocyte elastase. Molecular weight distrib ution of EDPs produced by partial and complete elastin digestion were compared by gel exclusion chromatography. A method for successful sepa ration of EDPs by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) is reported. The implications of these results for further immunological characterisation of these peptides are discussed with a view to stand ardisation of the techniques employed for the measurement of EDPs in v ivo.