Komatsu M, Tsukamoto I
Department of Food Science and Nutrition, Nara Women's University, Japan.
Biochim Biophys Acta. 1998 Feb 2;1379(2):289-96. doi: 10.1016/s0304-4165(97)00111-6.
The effects of folic acid on liver regeneration after partial hepatectomy were investigated. The injection of folic acid inhibited the increases in the activities of thymidylate synthase and thymidine kinase in regenerating rat liver at 24 h after partial hepatectomy, with a concomitant reduction in DNA content. Northern blot analysis showed that this inhibition was due to the delay of the elevation of the mRNA levels of thymidylate synthase and thymidine kinase after partial hepatectomy. At 48 and 72 h, after partial hepatectomy, the thymidylate synthase activities in the folic acid injected rats increased to about 1.9- and 1.7-fold the corresponding control level, respectively, while thymidine kinase activities were similar to the control. Immunoblotting assay indicated that the increases in the thymidylate synthase activity at 48 and 72 h after partial hepatectomy were caused by a three fold increase in its protein level. Folic acid suppressed chymotryptic hydrolysis of thymidylate synthase. These suggest that folic acid increases the protein level of thymidylate synthase, at least in part, through protection against proteolysis.
研究了叶酸对部分肝切除术后肝脏再生的影响。注射叶酸抑制了部分肝切除术后24小时大鼠再生肝脏中胸苷酸合成酶和胸苷激酶活性的增加，同时DNA含量降低。Northern印迹分析表明，这种抑制是由于部分肝切除术后胸苷酸合成酶和胸苷激酶mRNA水平升高的延迟。部分肝切除术后48小时和72小时，注射叶酸的大鼠胸苷酸合成酶活性分别增加到相应对照水平的约1.9倍和1.7倍，而胸苷激酶活性与对照相似。免疫印迹分析表明，部分肝切除术后48小时和72小时胸苷酸合成酶活性的增加是由于其蛋白质水平增加了三倍。叶酸抑制了胸苷酸合成酶的胰凝乳蛋白酶水解。这些表明叶酸至少部分地通过防止蛋白水解来增加胸苷酸合成酶的蛋白质水平。
