Bhattacharya P, Simet I, Basu S
Proc Natl Acad Sci U S A. 1979 May;76(5):2218-21. doi: 10.1073/pnas.76.5.2218.
The effects of concanavalin A and ricin (RCAII, Mr 65,000) on [3H]thymidine incorporation into human neuroblastoma IMR-32 DNA showed reduction of total DNA synthesis to 50% and 70% of control, respectively. Two DNA polymerase (DNA nucleotidyltransferase, EC 2.7.7.7.) activities (alpha and beta) involved in the biosynthesis in vitro of DNA were separated by sucrose density gradient centrifugation from IMR-32 cell homogenate. The DNA polymerase alpha activity was also purified by selective precipitation with polyethylene glycol (Mr 6000) followed by agarose-concanavalin A column chromatography. The activities of both DNA polymerases were examined at various concentrations of mutagenic and nonmutagenic plant agglutinins and the toxin ricin. Concanavalin A and ricin specifically inhibited DNA polymerase alpha activity (activity reduced to 19% and 10%, respectively), whereas DNA polymerase beta activity was inhibited (reduced to 16%) by red kidney bean agglutinin (PHA-P).
伴刀豆球蛋白A和蓖麻毒素（RCAII，分子量65,000）对[3H]胸腺嘧啶核苷掺入人神经母细胞瘤IMR-32 DNA的影响表明，总DNA合成分别降至对照的50%和70%。参与DNA体外生物合成的两种DNA聚合酶（DNA核苷酸转移酶，EC 2.7.7.7.）活性（α和β）通过蔗糖密度梯度离心从IMR-32细胞匀浆中分离出来。DNA聚合酶α活性也通过用聚乙二醇（分子量6000）选择性沉淀，随后进行琼脂糖-伴刀豆球蛋白A柱色谱法进行纯化。在各种浓度的诱变和非诱变植物凝集素以及毒素蓖麻毒素条件下检测了两种DNA聚合酶的活性。伴刀豆球蛋白A和蓖麻毒素特异性抑制DNA聚合酶α活性（活性分别降至19%和10%），而DNA聚合酶β活性被菜豆凝集素（PHA-P）抑制（降至16%）。
