The isoforms of human neutrophil elastase and cathepsin G differ in their carbohydrate side chain structures.
The two proteinases found in human neutrophil granules, elastase and cathepsin G, each are normally isolated as a mixture of isoforms differing only in carbohydrate content. Elastase has two N-glycosylation sites occupied (Asn-45 and Asn-144), whereas cathepsin G has only one (Asn-64). Analysis of a minor form of elastase (E-1) and cathepsin G (C-1) indicates that the carbohydrate structures at each glycosylation site are complex-type bi-antennary chains usually associated with secretory glycoproteins. In contrast, the isoforms E-3 and C-3, the major forms of elastase and cathepsin G respectively, contain exclusively truncated, oligomannose-type chains at the same positions in the sequence of each protein. These data suggest the possibility that certain elastase and cathepsin G isoforms (E-1 and C-1) might be destined for secretory, others (E-3 and C-3) for lysosomal functions.
Watorek
W
W
Institute of Biochemistry, Wroclaw University, Poland.
van Halbeek
H
H
Travis
J
J
D000595:Amino Acid Sequence; D002236:Carbohydrate Conformation; D050260:Carbohydrate Metabolism; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000032:analysis*; D056649:Cathepsin G; D002403:Cathepsins / Q000737:chemistry* / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D006026:Glycoside Hydrolases / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D007527:Isoenzymes; D019272:Leukocyte Elastase; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000201:enzymology*; D010196:Pancreatic Elastase / Q000737:chemistry* / Q000302:isolation & purification; D012697:Serine Endopeptidases
D002241:Carbohydrates; D007527:Isoenzymes; D006026:Glycoside Hydrolases; D002403:Cathepsins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G; D010196:Pancreatic Elastase; D019272:Leukocyte Elastase