Column separation using Bio-Gel P100 for the characterization of the products of human lung elastin degradation by leucocyte elastase and cathepsin G.
The solubilization of human lung elastin by leucocyte elastase and cathepsin G is described. Elastolysis kinetic studies clearly show that leucocyte elastase is more efficient in solubilizing elastin fibres than is cathepsin G. Cathepsin G can degrade elastin but at a much slower rate. Characterization of elastase and cathepsin G soluble elastin fragments, obtained after 24 h of digestion (enzyme-substrate ratio, 1:100), was first performed by isoelectric focusing. Whole digests were focused as 6 bands in a pH range 4.2 to 4.7 and were found to have no significant differences in amino acid compositions. Biogel P-100 gel filtration of the elastase digested fragments separated a major excluded fraction (Mr's: 80,000 to 30,000) and a small retained one (Mr's: 6000 to 4000). Conversely, cathepsin G digests were eluted as a minor excluded fraction and a more important retarded one (Mr's: 6000 to 4000). Only the high molecular weight fractions of both enzymes digests contain crosslinked amino acids; this assigns a role for desmosines in the resistance of elastin to these proteases. These results are discussed in comparison with the data obtained by others.
D000596:Amino Acids / Q000032:analysis; D056649:Cathepsin G; D002403:Cathepsins / Q000378:metabolism*; D002850:Chromatography, Gel; D004549:Elastin / Q000378:metabolism*; D006801:Humans; D007525:Isoelectric Focusing; D019272:Leukocyte Elastase; D008168:Lung / Q000201:enzymology / Q000378:metabolism*; D010196:Pancreatic Elastase / Q000378:metabolism*; D012697:Serine Endopeptidases
D000596:Amino Acids; D004549:Elastin; D002403:Cathepsins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G; D010196:Pancreatic Elastase; D019272:Leukocyte Elastase