Tissue (type II) transglutaminase covalently incorporates itself, fibrinogen, or fibronectin into high molecular weight complexes on the extracellular surface of isolated hepatocytes: Use of 2-((2-oxopropyl)thio)-imidazolium derivatives as cellular transglutaminase inactivators

Rabbit hepatocyte surface-expressed tissue (type II) transglutaminase is shown to act as a binding site for fibrinogen or fibronectin and to covalently incorporate these glycoproteins, in addition to itself, into extracellular high molecular weight complexes. This concept is supported by the observation that a nonpeptidyl, active site-directed transglutaminase inactivator (L683685) elicited concentration-dependent (0.1 - 10 mu m) decreases in the calcium-dependent binding and covalent cross-linking of super(125)I-fibrinogen, super(125)I-fibronectin, or ( super(14)C)putrescine by hepatocyte suspensions. In corroboration with these findings, an antiserum against rabbit liver transglutaminase, which did not cross-react with rabbit factor XIII, elicited concentration-dependent decreases in the calcium-dependent binding and covalent cross-linking of super(125)I-fibrinogen or ( super(14)C)putrescine by hepatocyte suspensions.