Elastolytic activity of peripheral blood monocytes.
Human peripheral blood monocytes have been purified by Ficoll-Hypaque density gradient centrifugation and adherence to plastic dishes, and assayed for elastolytic activity using insoluble [3H]elastin. Approximately 5-10 micrograms of elastin are solubilized at pH 7.5 per mg protein per h. The specific activity in monocytes varies between 3 and 15% of that of neutrophils obtained at the same time from the same subjects. The enzymatic activity derives principally from monocytes. Lymphocytes purified by Sephadex G-10 gel filtration chromatography exhibit only trace elastolytic activity, while neutrophils comprise 1% or less of the cell population. Monocyte elastolytic activity is inhibited by alpha-1-antitrypsin and Succinyl-Ala-Ala-Pro-Val-chloromethylketone indicating that it is a serine-type protease. When extracts of monocytes are analyzed by gel filtration, the elastolytic activity appears in large molecular weight forms; however, these forms are not observed when extracts of monocyte lysosomes are analyzed. Such variation in forms is also seen with neutrophil extracts. Monocytes are a source of elastolytic activity for various physiologic and pathologic actions in the lung and other organs.
D002458:Cell Fractionation; D002469:Cell Separation; D004549:Elastin / Q000097:blood*; D006801:Humans; D007962:Leukocytes / Q000201:enzymology; D009000:Monocytes / Q000166:cytology / Q000201:enzymology*; D009504:Neutrophils / Q000166:cytology; D010196:Pancreatic Elastase / Q000097:blood* / Q000302:isolation & purification; D014316:Tritium
D014316:Tritium; D004549:Elastin; D010196:Pancreatic Elastase