Sender P M, Garlick P J
Biochem J. 1973 Mar;132(3):603-8. doi: 10.1042/bj1320603.
The synthesis rates of total heart protein and of sarcoplasmic and myofibrillar protein fractions have been determined by perfusion of isolated rat hearts with [(14)C]tyrosine at constant specific radioactivity. In hearts perfused without insulin, both myofibrillar and sarcoplasmic proteins were synthesized at a fractional rate of 10-11% per day. This corresponds to a half-life for synthesis of about 7 days. The effect of added insulin was to increase the rate of heart-protein synthesis to a half-life of 3-4 days. With hearts perfused via the left atrium and performing external work, there was a rise in the specific radioactivity of intracellular free tyrosine, and the half-life for synthesis of proteins was 3-4 days. The extent of labelling of individual myofibrillar proteins was estimated after polyacrylamide-gel electrophoresis of solubilized myofibrils in the presence of sodium dodecyl sulphate. No particular protein showed an unusually high or low specific radioactivity after labelling in perfusion. Insulin caused a general increase in labelling of all the proteins analysed.
通过以恒定比放射性的[(14)C]酪氨酸灌注离体大鼠心脏，测定了心脏总蛋白以及肌浆蛋白和肌原纤维蛋白组分的合成速率。在无胰岛素灌注的心脏中，肌原纤维蛋白和肌浆蛋白的合成分数速率均为每天10 - 11%。这相当于合成的半衰期约为7天。添加胰岛素的作用是将心脏蛋白合成速率提高至半衰期为3 - 4天。对于经左心房灌注并进行外部做功的心脏，细胞内游离酪氨酸的比放射性升高，蛋白质合成的半衰期为3 - 4天。在十二烷基硫酸钠存在的情况下，对溶解的肌原纤维进行聚丙烯酰胺凝胶电泳后，估计了各个肌原纤维蛋白的标记程度。灌注标记后，没有特定蛋白质显示出异常高或低的比放射性。胰岛素导致所有分析蛋白质的标记普遍增加。
