Formation of neutrophil-activating peptide 2 from platelet-derived connective-tissue-activating peptide III by different tissue proteinases.
Neutrophil-activating peptide 2 (NAP-2) is generated by cleavage of two inactive precursors, connective-tissue-activating peptide III (CTAP-III) and platelet basic protein (PBP), which are stored in the alpha-granules of blood platelets. Using highly purified CTAP-III as the substrate we studied the generation of NAP-2 by several neutral tissue proteinases. CTAP-III was rapidly cleaved by chymotrypsin, cathepsin G and trypsin, yielding products with neutrophil-stimulating activity. This activity remained unchanged for 24 h in the presence of chymotrypsin, decreased only slowly in the presence of cathepsin G, but was rapidly destroyed by trypsin. CTAP-III was also degraded by human neutrophil elastase and porcine pancreatic elastase, but no active fragments were obtained. By contrast, no degradation of CTAP-III was observed with thrombin, plasmin or 'granzymes' from cytolytic T-lymphocyte granules. Two active fragments of CTAP-III, generated by chymotrypsin or cathepsin G, were purified and partially sequenced, and were found to have the same N-terminal sequence as NAP-2. These results indicate that both proteinases cleave preferentially the bond between amino acids 15 (Tyr) and 16 (Ala) of CTAP-III. We conclude that chymotrypsin-like proteolytic activity in the vicinity of activated platelets may generate NAP-2 intravascularly. Due to its presence in the primary granules of neutrophils and monocytes cathepsin G is likely to be involved in this process.
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Theodor-Kocher Institute, University of Bern, Switzerland.
Baggiolini
M
M
Walz
A
A
D000595:Amino Acid Sequence; D001792:Blood Platelets / Q000648:ultrastructure; D056649:Cathepsin G; D002403:Cathepsins / Q000378:metabolism; D018925:Chemokines; D002918:Chymotrypsin / Q000378:metabolism; D003594:Cytoplasmic Granules / Q000378:metabolism; D010450:Endopeptidases / Q000378:metabolism*; D006801:Humans; D016209:Interleukin-8 / Q000737:chemistry; D008969:Molecular Sequence Data; D010196:Pancreatic Elastase / Q000378:metabolism; D010452:Peptide Biosynthesis; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D012697:Serine Endopeptidases; D014357:Trypsin / Q000378:metabolism; D001620:beta-Thromboglobulin
D018925:Chemokines; D016209:Interleukin-8; C061615:PPBP protein, human; D010446:Peptide Fragments; D010455:Peptides; D011498:Protein Precursors; D011506:Proteins; D001620:beta-Thromboglobulin; C009862:connective tissue-activating peptide; D002403:Cathepsins; D010450:Endopeptidases; D012697:Serine Endopeptidases; D002918:Chymotrypsin; C534094:CTSG protein, human; D056649:Cathepsin G; D010196:Pancreatic Elastase; D014357:Trypsin