Shah D V, Suttie J W
Proc Natl Acad Sci U S A. 1971 Jul;68(7):1653-7. doi: 10.1073/pnas.68.7.1653.
Previous studies have shown that the vitamin K-induced synthesis of prothrombin in a vitamin K-deficient rat is only slightly inhibited by cycloheximide treatment. Rat prothrombin has now been purified by disc electrophoresis after BaSO(4) adsorption and citrate elution. When cycloheximide (5 mg/kg) was given to vitamin K-deficient rats 30 min before vitamin K, about 70% of the amount of prothrombin seen in rats not treated with cycloheximide was produced (two-stage assay), and the prothrombin band could be seen on the electrophoretic gels. However, if radioactive amino acids are administered to the rats after cycloheximide treatment, the newly formed prothrombin contains no radioactivity. The isolated prothrombin does contain radioactivity if the vitamin K-deficient rats are treated with vitamin K but no cycloheximide. When radioactive amino acids were given to deficient rats 1 hr before cycloheximide and vitamin K, radioactivity was found in prothrombin. These data suggest that, in the intact rat, the action of vitamin K is to convert a protein precursor with a short biological half life to prothrombin.
以往的研究表明，在维生素K缺乏的大鼠中，维生素K诱导的凝血酶原合成仅受到环己酰亚胺处理的轻微抑制。现在，通过硫酸钡吸附和柠檬酸盐洗脱后的圆盘电泳法，已将大鼠凝血酶原纯化。在给维生素K缺乏的大鼠注射维生素K前30分钟给予环己酰亚胺（5毫克/千克），经两阶段测定，所产生的凝血酶原量约为未用环己酰亚胺处理的大鼠的70%，并且在电泳凝胶上可以看到凝血酶原条带。然而，如果在环己酰亚胺处理后给大鼠注射放射性氨基酸，新形成的凝血酶原不含放射性。如果给维生素K缺乏的大鼠注射维生素K但不注射环己酰亚胺，分离出的凝血酶原确实含有放射性。当在给环己酰亚胺和维生素K前1小时给缺乏大鼠注射放射性氨基酸时，在凝血酶原中发现了放射性。这些数据表明，在完整的大鼠中，维生素K的作用是将具有短生物半衰期的蛋白质前体转化为凝血酶原。
