Transglutaminase-catalysed cross-linking: a potential mechanism for the interaction of fibrinogen, low density lipoprotein and arterial type III procollagen.

Bovine type III [3H]procollagen or its [125I]aminopropeptide were shown by chromatography under dissociating conditions to form very high molecular weight compounds with excess bovine fibrinogen after incubation with purified tissue transglutaminase, though none is formed with other major plasma proteins. Larger compounds of this type formed from fibrinogen or fibrin monomer can be separated by centrifugation and they are insoluble on washing with 1% SDS. Ultracentrifugation showed that a significant fraction of [3H]procollagen III forms a low density complex on incubation with transglutaminase plus excess IDL or LDL, but not HDL. SDS polyacrylamide gel electrophoresis showed that type III collagen [125I]aminopropeptide forms high molecular weight compounds after incubation with transglutaminase plus excess IDL or LDL but not with HDL. It is hypothesized that, in the presence of excessive concentrations of LDL and/or fibrinogen and of tissue transglutaminase, crosslinking reactions of the type demonstrated may interfere with normal injury-repair processes and stimulate the formation of atherosclerotic lesions in arteries.