Tamura Y, Orino S, Saijyo Y, Nishimoto T, Nagase N, Mori H
Heart Vessels. 1986;2(4):202-7. doi: 10.1007/BF02059969.
The relations of the light chains of myosins of the atria, ventricles, and atrioventricular conducting tissue (specialized myocardial tissue) and the distribution of the light chains of myosin in different regions of the atrioventricular conducting tissue in bovine heart were examined. Two-dimensional gel electrophoresis showed that the atrial and ventricular myosins each had two light chains (LC1 and LC2). Ventricular LC1 differed from atrial LC1, but ventricular LC2 corresponded to atrial LC2. The specialized myocardial tissue myosin had three light chains (named here SL1, SL2, and SL3). SL1 comigrated with ventricular LC1, SL2 with atrial LC1, and SL3 with ventricular LC2 and atrial LC2. The compositions of the three light chains of myosins in various regions of the atrioventricular conducting tissue were determined by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The percentage proportion of SL1 decreased in the order--atrioventricular node (AVN), right and left bundle branches (RLBB), His bundle (HIS), false tendon (FT) myosin; while the percentage proportion of SL2 decreased in the order--FT and HIS, RLBB, AVN myosin. The percentages of SL3 in these four regions were similar. The Ca2+-activated ATPase activity of myosin was highest in the AVN and lowest in the FT. The activities in the HIS and RLBB were intermediate between those in the AVN and FT. Thus, the composition of the light chains and the Ca2+-activated ATPase activity were different in various regions of the atrioventricular conducting tissue.
研究了牛心脏心房、心室和房室传导组织（特殊心肌组织）中肌球蛋白轻链的关系以及肌球蛋白轻链在房室传导组织不同区域的分布。二维凝胶电泳显示，心房和心室肌球蛋白各有两条轻链（LC1和LC2）。心室LC1与心房LC1不同，但心室LC2与心房LC2相对应。特殊心肌组织肌球蛋白有三条轻链（此处命名为SL1、SL2和SL3）。SL1与心室LC1迁移位置相同，SL2与心房LC1迁移位置相同，SL3与心室LC2和心房LC2迁移位置相同。通过十二烷基硫酸钠（SDS）-聚丙烯酰胺凝胶电泳测定了房室传导组织不同区域肌球蛋白三条轻链的组成。SL1的百分比比例按以下顺序降低——房室结（AVN）、左右束支（RLBB）、希氏束（HIS）、假腱索（FT）肌球蛋白；而SL2的百分比比例按以下顺序降低——FT和HIS、RLBB、AVN肌球蛋白。这四个区域中SL3的百分比相似。肌球蛋白的Ca2+激活ATP酶活性在AVN中最高，在FT中最低。HIS和RLBB中的活性介于AVN和FT中的活性之间。因此，房室传导组织不同区域的轻链组成和Ca2+激活ATP酶活性不同。
