Dankert J R, Papadi G P, Shields R P
Department of Comparative and Experimental Pathology, College of Veterinary Medicine University of Florida, Gainesville 32610.
Microsc Res Tech. 1992 Feb 1;20(3):281-7. doi: 10.1002/jemt.1070200308.
Creatine phosphokinase regenerates ATP from ADP using creatine phosphate. Isoenzymes of creatine phosphokinase are bound to certain cellular structures or are compartmentalized in areas of the cell, and this has been used as a basis for defining the role of these isoenzymes in energy metabolism. The M isoenzyme of creatine phosphokinase has been morphologically associated with the M-line of striated muscle in many species. In this present study the ultrastructural distribution and the relative concentration of the M form of creatine phosphokinase in human muscle tissue was determined using immunogold and electron microscopy. The M-line of the sarcomere, comprising only 3-4% of the sarcomere area, was found to contain over 20% of the total M isoenzyme signal of the entire sarcomere. This technique represents a quantitative, ultrastructural method to study the subcellular distribution of this isoenzyme. These data suggest that localized concentrations of M-CPK may be important for normal energy metabolism, and may also serve as a foundation for a better understanding of the relationship between abnormal creatine metabolism and the pathogenesis of neuromuscular disease.
肌酸磷酸激酶利用磷酸肌酸从二磷酸腺苷（ADP）再生三磷酸腺苷（ATP）。肌酸磷酸激酶的同工酶与某些细胞结构结合或在细胞区域内进行分隔，这已被用作定义这些同工酶在能量代谢中作用的基础。在许多物种中，肌酸磷酸激酶的M同工酶在形态上与横纹肌的M线相关。在本研究中，使用免疫金和电子显微镜确定了人肌肉组织中肌酸磷酸激酶M型的超微结构分布和相对浓度。肌节的M线仅占肌节面积的3 - 4%，却发现其包含整个肌节总M同工酶信号的20%以上。该技术是一种研究这种同工酶亚细胞分布的定量超微结构方法。这些数据表明，M - CPK的局部浓度可能对正常能量代谢很重要，也可能为更好地理解肌酸代谢异常与神经肌肉疾病发病机制之间的关系奠定基础。
