Purification and N-terminal amino-acid sequence analysis of rabbit neutrophil cathepsin G.
Cathepsin G was isolated from granules of rabbit bloodstream leukocytes and purified to apparent homogeneity by a multi-step procedure consisting of ammonium sulphate precipitation, affinity chromatography on elastin-Sepharose, and finally by ion-exchange chromatography on a CM-52 column. The molecular weight of the enzyme, as determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), was 27,000. The first 24 N-terminal amino-acids were determined and showed 96%, 92% and 79% identity respectively to those of human, dog and rat cathepsin G. Despite the difference in the total amino-acid composition of cathepsin G between rabbit and other mammalian species, close similarities have been found in their substrate specificity and inhibition profile. The kcat/Km values of rabbit cathepsin G with Suc-Ala2-Pro-Phe-NA and Suc-Ala2-Pro-Leu-NA are quite similar to those reported for human cathepsin G under the same conditions. The inhibition profile of the isolated enzyme indicates that cathepsin G from rabbits, like that from other mammalians species belongs to the group of serine proteinases. Finally, like human cathepsin G, catalytically active rabbit enzyme is able to induce platelet aggregation.
Cavarra
E
E
Institute of General Pathology, University of Siena, Italy.
Santucci
A
A
Lungarella
G
G
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis*; D000818:Animals; D056649:Cathepsin G; D002403:Cathepsins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification*; D006801:Humans; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000201:enzymology*; D010196:Pancreatic Elastase / Q000378:metabolism; D011817:Rabbits; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases
D000596:Amino Acids; D002403:Cathepsins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G; C534097:Ctsg protein, rat; D010196:Pancreatic Elastase