Tsuda M, Umezawa Y, Masuyama M, Nozaki S F, Yamaguchi K, Katsunuma T
Department of Biochemistry, School of Medicine, Tokai University, Kanagawa, Japan.
Tokai J Exp Clin Med. 1988 Dec;13(6):329-36.
The effect of alpha-1-antichymotrypsin (ACT), which is known as an efficient serum protease inhibitor and is detected in tumor cell nuclei, on DNA synthesis was studied. ACT inhibited the activity of DNA polymerase alpha purified from human stomach adenocarcinoma. Other human serum proteins including serum albumin, alpha-1-acidglycoprotein, alpha-1-antitrypsin, and immunoglobulin G, as well as other protease inhibitors, such as leupeptin, pepstatin, PMSF and chymostatin, did not affect the activity of DNA polymerase alpha. It was therefore concluded that the inhibitory action of ACT on DNA polymerase alpha was direct phenomenon unrelated to its protease inhibitory activity. Furthermore, the effect of ACT on DNA synthesis was also studied using lysolecithin-permeabilized cultured human stomach carcinoma cells. ACT added in the medium inhibited DNA synthesis and the degree of inhibition depended on incubation time. It was proportional to ACT concentration and the concentration of ACT required for 50% inhibition was 0.8 mg/ml.
研究了α-1-抗糜蛋白酶（ACT）对DNA合成的影响。ACT是一种高效的血清蛋白酶抑制剂，可在肿瘤细胞核中检测到。ACT抑制了从人胃腺癌中纯化的DNA聚合酶α的活性。其他人类血清蛋白，包括血清白蛋白、α-1-酸性糖蛋白、α-1-抗胰蛋白酶和免疫球蛋白G，以及其他蛋白酶抑制剂，如亮抑酶肽、胃蛋白酶抑制剂、苯甲基磺酰氟和抑糜酶素，均不影响DNA聚合酶α的活性。因此得出结论，ACT对DNA聚合酶α的抑制作用是一种与其蛋白酶抑制活性无关的直接现象。此外，还使用溶血卵磷脂通透的培养人胃癌细胞研究了ACT对DNA合成的影响。培养基中添加的ACT抑制了DNA合成，抑制程度取决于孵育时间。它与ACT浓度成正比，50%抑制所需的ACT浓度为0.8mg/ml。
