Release of Dog Polymorphonuclear Leukocyte Cathepsin G, Normally and in Endotoxin and Pancreatitic Shock. Isolation and Partial Characterization of Dog Polymorphonuclear Leukocyte Cathepsin G

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Abstract
Dog polymorphonuclear leukocyte cathepsin G was isolated from a granule extract using a two-step procedure including affinity chromatography on aTrasylol-Sepharose gel and ion-exchange chromatography on a CM 52 column. 22 of the first 24 N-terminal amino acids were determined and showed 83% and 71% identity to those of human and rat cathepsin G, respectively. Total amino-acid composition demonstrated the basic nature of the protein. In an SDS/polyacrylamide-gel electrophoresis the protein showed an Mr of 29400 compared to the Mr of 26800 calculated from the total amino-acid composition. The enzyme was shown to form complexes with α1α2-macroglobulin and arproteinase inhibitor. A specific enzyme-linked immunosorbent assay was developed for the determination of cathepsin G/α proteinase inhibitor complex in dog plasma and tissue fluids. The mean concentration of cathepsin G in normal dog plasma was determined to be 38 μ/l, measured as cathepsin G/α1-proteinase inhibitor complex. When active dog cathepsin G was added to normal dog plasma in vitro, approximately 56% could be measured by the assay. Slow intravenous infusion of a lethal dose of endotoxin in dogs was followed by a marked drop in white blood cell count and thrombocytes and a simultaneous rapid increase in plasma cathepsin G concentration, reaching a maximum level of 150 β/l. Bile-induced experimental pancreatitis in dogs was accompanied by successive increase in cathepsin G levels in plasma as well as in peritoneal exudates, reaching a maximum level of about 300 μ/l in plasma and 18 mg/ l in the exudates during the late stages of disease. & by Walter de Gruyter & C