Extended cleavage specificity of human neutrophil cathepsin G: A low activity protease with dual chymase and tryptase-type specificities

Abstract Neutrophils and monocytes express cathepsin G and elastase and also can bind to activated platelets, thus they can be localized to the site of active coagulation. Early studies suggested that cathepsin G and elastase inactivated factor VIII (FVIII) and were thus anticoagulant. But other studies have suggested procoagulant functions for cathepsin G and elastase in activation of factor V or activation of platelets among other possible mechanisms. Therefore, we investigated the effects of human neutrophil elastase and human neutrophil cathepsin G on FVIII/VIIIa. Elastase does inactivate both FVIII and FVIIIa but cathepsin G activates FVIII while having very little effect on FVIIIa. Cathepsin G activation of FVIII is enhanced by phospholipid vesicles, apparently due to enhanced rate of cleavage and stabilization of the resulting molecule. The maximum level of activation is less than that of thrombin, but it is still four-fold as measured in an APTT assay. Cleavage sites for both proteases in FVIII were identified by Edman degradation and gel analysis. FVIII cleavages are limited to a few specific sites that are mostly located near known activating and inactivating cleavage sites. A notable exception is a cleavage site for elastase after valine 26 in the A1 domain. Cathepsin G cleavage sites near to thrombin cleavage sites likely contribute to the partial activation of FVIII. The unique elastase cleavage site at valine 26 likely contributes to the inactivation of FVIII and FVIIIa. Therefore, it is possible that neutrophils and monocytes may provide some pro-coagulant effect by activating FVIII and may also provide negative feedback by inactivating FVIIIa as well.

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Enzymatic and Molecular Biochemical Characterizations of Human Neutrophil Elastases and a Cathepsin G-like Enzyme

Molecules and Cells ◽

10.1007/s10059-000-0498-2 ◽

2000 ◽

Vol 10 (5) ◽

pp. 498-504 ◽

Cited By ~ 2

Author(s):

Woo Mi Kim ◽

Kooil Kang

Keyword(s):

Human Neutrophil ◽

Cathepsin G

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Identification of Constituents of Human Neutrophil Azurophil Granules That Mediate Fungistasis againstHistoplasma capsulatum

Infection and Immunity ◽

10.1128/iai.68.10.5668-5672.2000 ◽

2000 ◽

Vol 68 (10) ◽

pp. 5668-5672 ◽

Cited By ~ 64

Author(s):

Simon L. Newman ◽

Lisa Gootee ◽

Joelle E. Gabay ◽

Michael E. Selsted

Keyword(s):

Human Neutrophil ◽

Histoplasma Capsulatum ◽

Cathepsin G ◽

Human Neutrophils ◽

Dependent Manner ◽

Subsequent Growth ◽

Concentration Dependent Manner ◽

Fungistatic Activity ◽

Maximum Inhibition ◽

Azurophil Granule

ABSTRACT Previously we demonstrated that human neutrophils mediate potent and long-lasting fungistasis against Histoplasma capsulatumyeasts and that all of the fungistatic activity resides in the azurophil granules. In the present study, specific azurophil granule constituents with fungistatic activity were identified by incubation with H. capsulatum yeasts for 24 h and by quantifying the subsequent growth of yeasts via the incorporation of [3H]leucine. Human neutrophil defensins HNP-1, HNP-2, and HNP-3 inhibited the growth of H. capsulatum yeasts in a concentration-dependent manner with maximum inhibition at 8 μg/ml. At a concentration of 4 μg/ml, all possible paired combinations of defensins exhibited additive fungistatic activity against H. capsulatum yeasts. Cathepsin G and bactericidal-permeability-increasing protein (BPI) also mediated fungistasis against H. capsulatum in a concentration-dependent manner. The fungistatic activities of combinations of cathepsin G and BPI were additive, as were those of combinations of cathepsin G or BPI with HNP-1, HNP-2, and HNP-3. Lysozyme and elastase exhibited modest antifungal activity, and azurocidin and proteinase 3 exhibited no significant fungistasis against H. capsulatum yeasts. Thus, defensins, cathepsin G, and BPI are the major anti-H. capsulatum effector molecules in the azurophil granules of human neutrophils.

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Action of human cathepsin G on the oxidized B chain of insulin

Biochemical Journal ◽

10.1042/bj1610017 ◽

1977 ◽

Vol 161 (1) ◽

pp. 17-19 ◽

Cited By ~ 28

Author(s):

A M J Blow ◽

A J Barrett

Keyword(s):

Amino Acid ◽

Amino Acid Composition ◽

Acid Composition ◽

Human Neutrophil ◽

Cathepsin G ◽

British Library ◽

Neutral Proteinase ◽

Terminal Residue ◽

Human Cathepsin ◽

Chymotrypsin A

The specificity of cathepsin G, a serine neutral proteinase from human neutrophil leucotyes, was determine dby its action on the insulin B chain. The most susceptible bonds were Phe-24-Phe-25, Leu-15-Tyr-16 and Tyr-16-Leu-17. Other bonds hydrolysed were Leu-6-Cys(O3H)-7, Leu-11-Val-12, Leu-17-Val-18 and Phe-25-Tyr-26. These results suggest that the specificity of cathespin G is closer to that of pig chymotrypsin C than ox Chymotrypsin A. Tables listing amino acid composition, N-terminal residue, and yields of isolated peptides have been deposited as Supplementary Publication SUP 50 075 (8 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7B2, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1977) 161,1.

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