The site of phosphorylation of troponin I in the perfused rabbit heart. The effect of adrenaline.
The site of phosphorylation of troponin I in the perfused rabbit heart. The effect of adrenaline.
复制标题
灌注兔心脏中肌钙蛋白 I 的磷酸化位点。
作者：
A. Moir;R. Solaro;S. Perry
1.经肾上腺素处理的兔心，肌钙蛋白I的共价结合磷酸盐总量由1.14摩尔/摩尔增加到1.86摩尔/摩尔。2.共价结合的磷酸只能在由残基1-48组成的心肌肌钙蛋白I分子区域被鉴定。3.当~(32)P标记的正磷酸盐存在于灌流液中时，丝氨酸-20处的磷酸盐被放射性标记。这个残基是唯一能被鉴定的重要的磷酸化位点。4.肾上腺素的加入使共价结合的[~(32)P]磷酸增加了4-5倍。几乎所有的32P都位于丝氨酸-20上。5.上述结果表明，在肾上腺素存在的情况下，心肌肌钙蛋白I丝氨酸-20的磷酸化程度从对照组的30-40%增加到约100%。
1. On treatment of the perfused rabbit heart with adrenaline, the total covalently bound phosphate of troponin I increased from 1.14 mol of phosphate/mol to 1.86 mol of phosphate/mol. 2. Covalently bound phosphate could be identified only in the region of the molecule of cardiac troponin I consisting of residues 1--48. 3. When 32P-labelled orthophosphate was present in the perfusion medium the phosphate at serine-20 became radioactively labelled. This residue was the only significant site of phosphorylation that could be identified. 4. The addition of adrenaline caused a 4--5-fold increase in covalently bound [32P]phosphate. Virtually all of the 32P was located at serine-20. 5. It was concluded from these studies that the extent of phosphorylation of serine-20 of cardiac troponin I increased from 30--40% in the control perfused heart to about 100% in the presence of adrenaline.