Functional Kunitz inhibitor binding domain in plasmin-derived light chain as shown by affinity chromatography.

The light chain of plasmin, prepared by selective reduction of the interchain disulfide bridges, can be separated from the heavy chain by affinity adsorption onto Kunitz inhibitor/Sepharose. This adsorption involves the active center of plasmin because it does not occur if the light chain is derived from a plasmin previously blocked by the active site titrant p-nitrophenyl-p'-guanidinobenzoate. It can be deduced that the conformation of the inhibitor binding domain of plasmin is preserved in the free light chain.