子宫内绵羊胎儿的全身及组织蛋白质合成分数

Whole body and tissue fractional protein synthesis in the ovine fetus in utero.

作者信息

Schaefer A L, Krishnamurti C R

出版信息

Br J Nutr. 1984 Sep;52(2):359-69. doi: 10.1079/bjn19840102.

DOI:10.1079/bjn19840102

Abstract

Whole-body and tissue fractional protein synthesis rates were determined in chronically-catheterized ovine fetuses at 120-130 d of gestation following an 8 h continuous infusion of L-[U-14C]- or L-[2,3,5,6-3H]tyrosine. From the net utilization of tyrosine by the fetus, corrected for apparent oxidation, and tyrosine concentration in the fetal carcass protein, whole-body protein synthesis was estimated to be 63 g/d per kg. Following 8 h of infusion of labelled tyrosine the ewes were killed and fetal tissues were removed for the determination of tyrosine specific activity. The fractional rate of protein synthesis (ks) was calculated from the specific activity ratio, protein bound:intracellular free tyrosine. Tissue ks values for the liver, kidney, lungs, brain, skeletal muscle and small intestine were 78, 45, 65, 37, 26 and 93%/d respectively. The absolute rate of synthesis was calculated by multiplying the tissue protein content by ks. Muscles, gastrointestinal tract, liver and lungs contributed approximately 20.5, 20.5, 14.4 and 9.4% respectively to whole-body protein synthesis. The efficiency of protein synthesis as expressed by the RNA activity was higher in liver, lung and brain followed by kidney, skeletal and cardiac muscle.

摘要

在妊娠120 - 130天的慢性插管绵羊胎儿中，连续8小时输注L-[U-14C]-或L-[2,3,5,6-3H]酪氨酸后，测定全身和组织的蛋白质合成分数率。根据胎儿对酪氨酸的净利用率（校正表观氧化）以及胎儿胴体蛋白中的酪氨酸浓度，估计全身蛋白质合成量为每千克每天63克。在输注标记酪氨酸8小时后，处死母羊并取出胎儿组织以测定酪氨酸比活性。蛋白质合成分数率（ks）由蛋白质结合型：细胞内游离酪氨酸的比活性计算得出。肝脏、肾脏、肺、脑、骨骼肌和小肠的组织ks值分别为78%/天、45%/天、65%/天、37%/天、26%/天和93%/天。合成绝对速率通过将组织蛋白含量乘以ks来计算。肌肉、胃肠道、肝脏和肺分别对全身蛋白质合成贡献约20.5%、20.5%、14.4%和9.4%。以RNA活性表示的蛋白质合成效率在肝脏、肺和脑中较高，其次是肾脏、骨骼肌和心肌。