[Human low molecular weight kininogen: preparation, purification and immunochemical properties]

A purified preparation of low molecular weight kininogen (LMWK) (Mr = 70 000+ +2 000) has been obtained from human blood plasma. The kinin content per 1 mg of the obtained preparation is 14--16 micrograms of bradykinin. A rabbit antiserum to LMWK which is free of antibodies against IgG and albumin present as admixtures in the kininogen preparation has been obtained. The titer of the antiserum as measured by dilution of antibodies, with normal human blood plasma as an antigen source, is 1 : 16. 1 ml of the antiserum binds 125 micrograms of purified LMWK in the equivalence zone. Immunoelectrophoretic studies of the antiserum to LMWK revealed three precipitation arcs with human plasma. It was assumed that these immunocomplexes are formed with a low and high molecular weight forms of kininogen and, possibly, with a high molecular weight kininogen complex with prekallikrein.