Seki S, Oda T
Biochim Biophys Acta. 1977 Dec 14;479(4):391-9. doi: 10.1016/0005-2787(77)90032-6.
The effect of heparin on DNA synthesis was compared between replicative DNA synthesis and unscheduled DNA synthesis. Replicative DNA synthesis in permeable cells or nuclei prepared from rapidly growing mouse ascites sarcoma cells was inhibited by heparin. Unscheduled DNA synthesis in nuclei isolated from normal rat liver or from mouse ascites sarcoma cells in stationary phase was stimulated by heparin at low concentrations but inhibited by high heparin concentrations. DNA polymerase activity assayed with activated calf thymus DNA and DNA polymerase alpha purified partially from mouse ascites sarcoma cells was inhibited with either calf thymus histones or heparin. DNA synthesis inhibited with histones was partially reactivated by heparin. Replicative DNA synthesis in permeable cells was inhibited by adding histones to the assay mixture, and the inhibited DNA synthesis was partially reactivated by low concentrations of heparin. These results indicated that the replicated sites (or replication machinery) in permeable cells or nuclei were largely unrestricted by histones and that heparin inhibition of replicative DNA synthesis was due to the direct inhibitory interaction of heparin with some essential component(s), such as DNA polymerase, of replication machinery.
在复制性DNA合成与非预定DNA合成之间比较了肝素对DNA合成的影响。肝素抑制了从快速生长的小鼠腹水肉瘤细胞制备的可渗透细胞或细胞核中的复制性DNA合成。低浓度肝素刺激从正常大鼠肝脏或处于静止期的小鼠腹水肉瘤细胞中分离出的细胞核中的非预定DNA合成，但高浓度肝素则抑制该合成。用活化的小牛胸腺DNA和从小鼠腹水肉瘤细胞中部分纯化的DNA聚合酶α测定的DNA聚合酶活性，无论是小牛胸腺组蛋白还是肝素都能抑制。组蛋白抑制的DNA合成可被肝素部分重新激活。向测定混合物中添加组蛋白可抑制可渗透细胞中的复制性DNA合成，低浓度肝素可部分重新激活被抑制的DNA合成。这些结果表明，可渗透细胞或细胞核中的复制位点（或复制机制）在很大程度上不受组蛋白的限制，并且肝素对复制性DNA合成的抑制是由于肝素与复制机制的某些必需成分（如DNA聚合酶）的直接抑制性相互作用。
