三尖杉酯碱抑制蛋白质合成过程中第一个肽键形成的新证据

本文采用无细胞体系分步实验的方法,得到了三尖杉酯碱抑制蛋白质生物合成过程中第一个肽键形成的新证据:在无转位作用的合成体系中,该药强烈地阻断二肽合成;在乙酰化苯丙氨酰-嘌呤霉素形成实验中,观察到该结合物的形成受到了抑制。     

STUDIES ON THE MECHANISM OF INDIRUBIN ACTION IN THE TREATMENT OF CHRONIC GRANULOCYTIC LEUKEMIA——V.BINDING BETWEEN INDIRUBIN AND DNA AND IDENTIFICATION OF THE TYPE OF BINDING

The binding between indirubin and calf thymus DNA in vitro has been verified by meansof the isotope labelling method, spectrophotometric method and thermal denaturation meas-urements. The λ_max 207 nm of indirubin shifted toward longer wave length with decrease ofabsorbance after the incubation of indirubin with DNA. The escalation of Tm value of DNAinduced by indirubin was about 2.4°C and it was reproducible. The binding force between themwas rather weak, as indirubin molecules were easily released during the precipitation withalcohol or the gel filtration. The binding was not affected by sodium chloride even at high con-centration but greatly decreased (to 20-30% of the control) in the presence of 8 M urea.These results showed that the binding between indirubin and DNA might be of hydrogen bondrather than ionic. The amount of bound ~3H-indirubin was directly proportional to the con-centration of indirubin. However, it increased abruptly when the concentration of indirubinreached 1.5×10~(-4) M. This     

靛玉红治疗慢性粒细胞白血病疗效原理的研究——靛玉红与DNA的结合作用及其结合键型的鉴别

本文应用吸收光谱分析法、同位素结合法、DNA融解曲线法及其它一些方法,证明了靛玉红与DNA之间具有结合作用。二者结合的最大分子比例(以靛玉红:脱氧核苷一磷酸计)为46:1000,结合反应的平衡常数K=5.7×10~6;结合作用发生迅速,无碱基特异性;热变性DNA能结合更多的药物分子;靛玉红与DNA结合的主要键型为氢键,但当靛玉红浓度大于一定限度时,还出现另一种形式的结合。     

NEW EVIDENCE FOR THE INHIBITION BY HARRINGTONINE IN THE FORMATION OF THE FIRST PEPTIDE BOND IN PROTEIN SYNTHESIS

New evidence for the inhibition by harringtonine in the formation of the first peptide bond in protein synthesis was obtained by means of experiments in the cell-free system. The antitumour drug strongly blocked dipeptide synthesis in the system without elongation factor G and GTP. Furthermore, it inhibited N-Acetyl-phenylalanyl-puromycin formation from NAcetyl-phenylalanyl-tRNA, puromycin, and ribosomes.