Specific binding of thrombin-antithrombin III complex to hepatocytes.
Thrombin-antithrombin III complex binds selectively to isolated hepatocytes, whereas antithrombin III alone does not. The binding is time and concentration dependent at 37 degrees C: the apparent Km value is 0.8/microM. The rate of binding is approximately 1.6 X 10(5) molecules h-1 cell-1 at this concentration. At 4 degrees C there is no measurable interaction between the complex and the hepatocytes. The binding is also prevented by pretreatment of cells with trypsin. On the other hand, about 80% of the thrombin-antithrombin III complex bound to hepatocytes is releasable by trypsin digestion. NaF or carboxyatractyloside does not inhibit the process. The interaction of thrombin-antithrombin III complex with hepatocytes seems to be specific, since the complexes of antithrombin III with other proteinases, like trypsin or plasmin, are not bound at the concentrations used. Based on these data, a mechanism for the binding of the inactive complexed form of thrombin to hepatocytes is suggested.
D000818:Animals; D000990:Antithrombin III / Q000378:metabolism*; D001665:Binding Sites; D002417:Cattle; D002478:Cells, Cultured; D005341:Fibrinolysin / Q000494:pharmacology; D006358:Hot Temperature; D006801:Humans; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D013917:Thrombin / Q000378:metabolism*; D013997:Time Factors; D014357:Trypsin / Q000494:pharmacology
D000990:Antithrombin III; D014357:Trypsin; D013917:Thrombin; D005341:Fibrinolysin