Purification and properties of heparin-releasable lipoprotein-associated coagulation inhibitor.
The lipoprotein-associated coagulation inhibitor (LACI) is present in vivo in at least three different pools: sequestered in platelets, associated with plasma lipoproteins, and released into plasma by intravenous heparin, possibly from vascular endothelium. In this study we have purified the heparin-relesable form of LACI from post-heparin plasma and show that it is structurally different from lipoprotein LACI. The purification scheme uses heparin-agarose chromatography, immunoaffinity chromatography, and size-exclusion chromatography and results in a 185,000-fold purification with a 33% yield. Heparin-releasable LACI (HRL), as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, under reducing conditions, appears as a major band at 40 Kd and a minor band at 36 Kd. Immunoblot analysis suggests that the 36-Kd band arises from carboxyl-terminus proteolysis that occurs during the purification. HRL has a specific activity similar to that of HepG2 or lipoprotein LACI. HRL and lipoprotein LACI combine with lipoproteins in vitro while purified HepG2 LACI does not. I125-labeled HRL, injected into a rabbit, is cleared more slowly than I125-labeled HepG2 LACI, which may be due to attachment to lipoproteins in vivo. Preliminary evidence suggests that HRL is associated with vascular endothelium, possibly by attachment to glycosaminoglycans.
Novotny
W F
WF
Division of Hematology/Oncology, Washington University School of Medicine, Jewish Hospital of St Louis, MO.
Palmier
M
M
Wun
T C
TC
Broze
G J
GJ
Miletich
J P
JP
D000328:Adult; D000595:Amino Acid Sequence; D001055:Apolipoproteins B / Q000097:blood; D001057:Apolipoproteins E / Q000097:blood; D001665:Binding Sites; D002460:Cell Line; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D005167:Factor VII / Q000037:antagonists & inhibitors* / Q000302:isolation & purification; D006493:Heparin / Q000097:blood / Q000494:pharmacology; D006801:Humans; D015151:Immunoblotting; D008071:Lipoprotein Lipase / Q000378:metabolism; D008074:Lipoproteins / Q000097:blood* / Q000302:isolation & purification; D008077:Lipoproteins, LDL / Q000097:blood / Q000302:isolation & purification; D008297:Male; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011480:Protease Inhibitors / Q000097:blood* / Q000302:isolation & purification; D012689:Sequence Homology, Nucleic Acid; D013925:Thromboplastin / Q000037:antagonists & inhibitors* / Q000302:isolation & purification
D001055:Apolipoproteins B; D001057:Apolipoproteins E; D008074:Lipoproteins; D008077:Lipoproteins, LDL; D011480:Protease Inhibitors; C051928:lipoprotein-associated coagulation inhibitor; D005167:Factor VII; D006493:Heparin; D013925:Thromboplastin; D008071:Lipoprotein Lipase