bleomycin-A2 and were more cytotoxic than the corresponding compounds lacking the DNA binding unit. On exposure of a mixture of cells and prodrugs to hypoxia and then air, the prodrug containing the nitrohistidine unit was not bioreductively activated but the prodrug having an N-oxide group was bioreductively activated. This result represents a novel approach to the improvement of the therapeutic ratio of
抗癌药
博来霉素的
金属络合区域的两个
吡啶类似物和两个相关但已失活的前药已与作为DNA结合单元的2,6-二苯基
吡啶衍生物连接。2,6-二苯基
吡啶系统在结构上与
博来霉素的细胞毒性的已知放大器有关。发现缀合物比
博来霉素-A2更牢固地结合DNA,并且比缺乏DNA结合单元的相应化合物更具细胞毒性。当细胞和前药的混合物暴露于低氧然后暴露于空气中时,含有硝基组
氨酸单元的前药未被
生物还原活化,但是具有N-氧化物基团的前药被
生物还原活化。该结果代表了改善
博来霉素类似物的治疗率的新方法。