Davanloo P, Crothers D M
Biochemistry. 1976 Nov 30;15(24):5299-305. doi: 10.1021/bi00669a016.
Three classes of kinetic behavior are observed in the complexes of actinomycin or ethidium with deoxydinucleotides. First, the initial dinucleotide binding to form a 1:1 complex is a rapid bimolecular process, whose rate could be measured for combination of actinomycin with d(pTpG) d(pGpT), d(pGpA), d(pGpG) d(pCpGpG), and d(pCpG) andfor combination of ethidium with d(pGpC). Second, with one exception, all reactions in which a second dinucleotide is added to form a 2:1 dinucleotide-drug complex are limited by a first-order step at high concentration. This class includes the combination of actinomycin with all dinucleotides tested except d(pGpC), and the reaction of ethidium with nucleotides of complementary sequence pyrimidine-purine, such as d(pCpG). The final class is the special case of d(pGpC) interacting to form a 2:1 complex with actinomycin. Third-order kinetics is observed, with no evidence for a first-order, rate-limiting step.
在放线菌素或溴化乙锭与脱氧二核苷酸的复合物中观察到三类动力学行为。首先，最初的二核苷酸结合形成1:1复合物是一个快速的双分子过程，其速率可通过放线菌素与d(pTpG)、d(pGpT)、d(pGpA)、d(pGpG)、d(pCpGpG)和d(pCpG)的结合以及溴化乙锭与d(pGpC)的结合来测量。其次，除了一个例外，所有添加第二个二核苷酸以形成2:1二核苷酸-药物复合物的反应在高浓度下都受一级步骤限制。这一类包括放线菌素与除d(pGpC)之外的所有测试二核苷酸的结合，以及溴化乙锭与互补序列嘧啶-嘌呤核苷酸（如d(pCpG)）的反应。最后一类是d(pGpC)与放线菌素相互作用形成2:1复合物的特殊情况。观察到三级动力学，没有一级限速步骤的证据。
