This study presents a method for detecting and characterizing
peptides of
elastin that result from lung matrix injury in
chronic obstructive pulmonary disease (
COPD). Lung
elastin degradation was studied by two representative in vivo elastases, human
neutrophil elastase (HNE) and macrophage
metalloproteinase (MMP12). The resulting
peptide mixtures were analyzed by high-performance liquid chromatography/electrospray tandem mass spectrometry (LC/MSMS) to characterize 40
elastin-derived
peptides (EDPs), 24 from HNE and 16 from MMP12 digestions. The
peptides constitute major EDPs that are solubilized by the enzymatic digestion. Using the selected reaction monitoring (SRM) from LC/MSMS analysis, the transition
ions of the
peptides were used to investigate the presence of the
peptides in selected body fluids of
chronic obstructive pulmonary disease (
COPD) patients. Four
peptides, GYPI, APGVGV, GLGAFPA, and VGVLPGVPT, were detected in plasma or sputum of some
COPD patients but not in normal controls. A hexapeptide
VGVAPG, which had been widely studied for its chemotactic activity for a possible pathogenic role in
COPD, was not detected in lung EDPs by HNE or MMP12 digestion, but only by porcine
pancreatic elastase (PPE) digestion. This study demonstrates a practical methodology to study
peptides from matrix degradations in
pulmonary disease and a means of investigating their pathogenesis.