[Purification of kininogen II (LMW) from human plasma]

Plasma supernatant in which kallikrein has been activated and removed by glass powder whilst kininogen I (HMW) has been consumed by the activated kallikrein, was used for the preparation of kininogen II. It was purified by chromatography on DEAE-cellulose followed by gel filtration on G-200 Sephadex. The purification of kininogen II was assessed from determinations of the amount of kinin released (expressed as bradykinin) as measured on the isolated guinea pig ileum, using samples incubated with human salivary kallikrein or trypsin. A preparation of kininogen II containing an activity equivalent to 8 microgram Br/mg protein, was obtained. Salivary kallikrein released approximately three times more kinin from the substrate as compared to trypsin.