Strekowski L, Mokrosz J L, Wilson W D
Department of Chemistry, Georgia State University, Atlanta 30303.
FEBS Lett. 1988 Dec 5;241(1-2):24-8. doi: 10.1016/0014-5793(88)81023-8.
The bleomycin-mediated digestion of DNA in the presence of ferrous ion, molecular oxygen, and dithiothreitol is characterized by a fast initial reaction, which is followed by a much slower process. The fast degradation is due to the fast activation of the bleomycin-Fe(II) complex and the subsequent fast reaction of the activated complex with DNA. The rate determining step for the slow process is reactivation of the bleomycin-Fe(III) complex. The apparent rate constants for both reactions increase with increasing ionic strength. The latter, unusual results are interpreted in terms of inhibition of bleomycin turnover by binding of cationic species with DNA at low ionic strength.
在亚铁离子、分子氧和二硫苏糖醇存在的情况下，博来霉素介导的DNA消化的特点是起始反应迅速，随后是一个慢得多的过程。快速降解是由于博来霉素-Fe(II)复合物的快速活化以及活化复合物与DNA随后的快速反应。慢过程的速率决定步骤是博来霉素-Fe(III)复合物的再活化。两个反应的表观速率常数都随离子强度的增加而增加。后一不寻常结果可根据低离子强度下阳离子物种与DNA结合对博来霉素周转的抑制来解释。
