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用硫酸钠-DEAE纤维素层析法从兔抗人肝癌铁蛋白的血清中提纯相应的IgG,回收率为68％。当IgG浓度为8mg/ml时,免疫效价为1:64。再用胃蛋白酶将IgG消化成F(ab′)_2,回收率为65％,分子量为92,000,效价较IgG略有降低。F(ab′)_2用10mM巯基乙醇在pH6.0、37℃的条件下反应1.5小时而被还原成Fab′,回收率达74％,分子量为46,000。Fab′分子中的巯基数为0.95～1.28,平均1.14和理论值1.0接近,符合酶标的要求。若延长还原时间将导致巯基数/分子增加,提示轻-重链间的二硫链亦被还原而可能导致抗体活力的丧失。
The corresponding IgG was purified from rabbit anti-human liver cancer ferritin serum by sodium sulfate-DEAE cellulose chromatography and the recovery was 68%. The immunological titer was 1:64 when the IgG concentration was 8 mg / ml. The IgG was digested with pepsin into F (ab ’) 2, with a recovery of 65% and a molecular weight of 92,000. The titer was slightly lower than that of IgG. F (ab ’) _ 2 was reduced to Fab’ by 10 mM mercaptoethanol at pH 6.0 and 37 ° C for 1.5 hours. The recovery rate was 74% and the molecular weight was 46,000. Fab ’molecules in the number of thiol 0.95 to 1.28, an average of 1.14 and the theoretical value of 1.0 close to meet the requirements of enzyme labeling. Increasing the reduction time leads to an increase in the number of sulfhydryl groups / molecules, suggesting that the light-heavy chain disulfide chain is also reduced and this may lead to a loss of antibody activity.