Miyama A, Kato T, Horai S, Yokoo J, Kashiba S
Biken J. 1975 Dec;18(4):193-204.
A complex formed between cobra venom factor (CVF) and isolated human factor B (B) was found to be converted by trypsin to a stable enzyme, CVF-B which cleaved the third component (C3) and the fifth component (C5) of human complement. The formation of CVF-B by trypsin required divalent cations, whereas the formation of the lytic factor from human serum occurred even in the presence of EDTA. CVF-B purified by gel filtration could initiate the hemolysis of unsensitized guinea pig erythrocytes when incubated with human complement components C5 to C9 in 0.01 M EDTA buffer. C3 was not required for the lysis of guinea pig erythrocytes initiated by CVF-B because of the beta1C precipitation line formed between human serum and anti-beta1C antibody did not inhibit the hemolysis by CVF-B in agarose gel. Treatment of beta1C and beta1F globulins in whole human serum with CVF-B in the presence of 0.01 M EDTA converted them to components with higher mobilities on immunoelectrophoresis.
发现眼镜蛇毒因子（CVF）与分离出的人B因子（B）形成的复合物可被胰蛋白酶转化为一种稳定的酶，即CVF - B，它能裂解人补体的第三成分（C3）和第五成分（C5）。胰蛋白酶形成CVF - B需要二价阳离子，而即使存在乙二胺四乙酸（EDTA），人血清中的溶细胞因子仍能形成。通过凝胶过滤纯化的CVF - B在0.01 M EDTA缓冲液中与人补体成分C5至C9一起孵育时，可引发未致敏豚鼠红细胞的溶血。由于人血清与抗β1C抗体之间形成的β1C沉淀线在琼脂糖凝胶中不抑制CVF - B的溶血作用，所以CVF - B引发豚鼠红细胞溶解不需要C3。在0.01 M EDTA存在的情况下，用CVF - B处理正常人血清中的β1C和β1F球蛋白，会使它们在免疫电泳中转化为迁移率更高的成分。
