Anti-Xa clotting activities in different hepatic-triglyceride lipase preparations from post-heparin plasma.
Two different preparations of hepatic triglyceride lipase (HTGL) with comparable lipolytic activities, purified from post-heparin human plasma, were assessed for their anti-Xa activities by two clotting and one chromogenic method. Preparation 1, prepared by heparin affinity followed by ion exchange chromatography, did not contain antithrombin III and exhibited no anti-Xa activity in any of the assay systems. Preparation 2, prepared by two consecutive heparin affinity chromatography steps, was active in all three assay systems, and was shown to contain antithrombin III (AT III). Addition of purified AT III to preparation 1 did not result in the anti-factor Xa activity of preparation 2, and monoclonal antibodies to AT III did not antagonize the activity of preparation 2. These results show that the anti-Xa activity of some HTGL preparations is neither due to the lipase itself nor to the content of AT III, but suggest, that it could be due to contamination with another protein, which binds to heparin sepharose columns but is removed during ion exchange chromatography. Most likely the effect is due to the extrinsic pathway inhibitor (EPI), also called lipoprotein-associated coagulation inhibitor (LACI), which has recently been shown to be released by heparin.
Schmidt
M
M
1st Department of Medicine, Faculty of Clinical Medicine Mannheim, University of Heidelberg, FRG.
Barrowcliffe
T W
TW
Gray
E
E
Watton
J
J
Harenberg
J
J
D000906:Antibodies / Q000097:blood*; D000937:Antigen-Antibody Reactions / Q000276:immunology; D000990:Antithrombin III / Q000502:physiology; D001780:Blood Coagulation Tests; D002863:Chromogenic Compounds / Q000378:metabolism; D015951:Factor Xa / Q000276:immunology*; D006493:Heparin / Q000097:blood*; D006801:Humans; D008049:Lipase / Q000097:blood*; D008099:Liver / Q000201:enzymology*
D000906:Antibodies; D002863:Chromogenic Compounds; D000990:Antithrombin III; D006493:Heparin; D008049:Lipase; D015951:Factor Xa