PROPERTIES OF LEUKOKININOGEN ISOLATED FROM HUMAN NEOPLASTIC ASCITES

Leukokininogen, the protein precursor of the vasoactive polypeptide leukokinin-H, has been isolated from human ovarian carcinoma ascites. A homogeneous preparation was achieved after a procedure consisting of ammonium sulfate fractionation, gel filtration with Sephadex G-200, DEAE-Sepharose ion exchange chromatography and preparative isoelectric focusing. Leukokininogen has an isoelectric pH of 4.56 and a molecular weight of about 41,000 daltons, determined by polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate. Kinin-like activity was generated from leukokininogen by incubation of the protein with the leukokininogenase from murine ascites tumor cells and with trypsin. Human plasma kallikrein does not release kinin activity from leukokininogen. The amino acid composition and immunological properties of leukokininogen demonstrate that leukokininogen is distinct from plasma bradykininogens. © 1979.