Human alpha 2 macroglobulin.

Human alpha 2 macroglobulin combines two unique features: the non-active site directed inhibition of virtually all endoproteases and the selective clearance of alpha 2 M-endoprotease complexes by receptor-mediated endocytosis. To study the molecular details of the mechanisms involved, primary amines were found to be worthwhile probes at three specific levels: the inactivation of native alpha 2 M, the derivatization by factor XIII and the cellular process of receptor-recycling. In this paper published data are supplemented with recently obtained evidence to discuss and speculate on the possible action or involvement of transglutaminase activities, indicated by the effects of the primary amines.