Structure of alpha 2-macroglobulin-protease complexes.

The analysis of thrombin-alpha 2M reaction mixtures by two-dimensional SDS-PAGE has allowed us to assign several probable molecular species to the mixture of complexes formed. These include structures previously described in, or predicted from, the literature, as well as two types of novel species: Divalent cross-linking of two inhibitor chains by a single enzyme molecule. Very high molecular weight species that are attributed to intermolecular cross-linking of more than one inhibitor molecule. Species containing enzyme monovalently linked to an intact subunit are not supported by our data, but are not excluded and additional study will be required to determine if they exist.