Frémont P, Charest P M, Côté C, Rogers P A
Muscle Biology Research Group, Laval University, Sainte-Foy, Québec, Canada.
J Histochem Cytochem. 1988 Jul;36(7):775-82. doi: 10.1177/36.7.3133407.
The objectives of the present study were to determine if carbonic anhydrase III (CA III) demonstrated a specific association for any particular organelle or structure of the skeletal muscle cell and to quantify the activity and content of this enzyme in different types of skeletal muscle fibers. Ultrastructural localization of CA III in the soleus (SOL), deep vastus lateralis (DVL), and superficial vastus lateralis (SVL), composed of predominantly type I, IIa, and IIb fibers, respectively, was performed using a high-resolution immunocytochemical technique and antibody specific for CA III on ultra-thin sections of skeletal muscle embedded in the water-soluble medium polyvinyl alcohol (PVA). The results indicated a uniform distribution of CA III within the sarcomere. Mitochondria, nuclei, triads, Z-, and M-bands were not specifically labeled. Immunoblotting of washed myofibril preparations did not show any detectable CA III associated with this structure. In addition to quantification of the immunogold labeling, CA III activity and content were assayed in the post-mitochondrial supernatant of the three muscles. In the SOL, these values were found to be 3.6-7.6 times higher than in the DVL. The SVL showed a labeling intensity slightly higher than background level, while the enzyme activity and content were indistinguishable from background levels. We therefore conclude that CA III is randomly distributed in the cytoplasm of the three muscle fiber types and that the relative CA III content and activity in the three muscles studied is SOL greater than DVL greater than SVL approximately equal to 0.
本研究的目的是确定碳酸酐酶III（CA III）是否与骨骼肌细胞的任何特定细胞器或结构存在特异性关联，并量化该酶在不同类型骨骼肌纤维中的活性和含量。使用高分辨率免疫细胞化学技术和针对CA III的抗体，对分别主要由I型、IIa型和IIb型纤维组成的比目鱼肌（SOL）、股外侧肌深层（DVL）和股外侧肌浅层（SVL）进行超微结构定位，这些骨骼肌超薄切片嵌入水溶性介质聚乙烯醇（PVA）中。结果表明CA III在肌节内分布均匀。线粒体、细胞核、三联体、Z线和M线均未被特异性标记。对洗涤后的肌原纤维制剂进行免疫印迹分析，未显示与该结构相关的任何可检测到的CA III。除了对免疫金标记进行定量外，还测定了这三块肌肉线粒体后上清液中的CA III活性和含量。在SOL中，这些值比DVL中的高3.6 - 7.6倍。SVL显示出略高于背景水平的标记强度，而酶活性和含量与背景水平无差异。因此，我们得出结论，CA III随机分布于三种肌纤维类型的细胞质中，并且在所研究的三块肌肉中，相对CA III含量和活性为SOL大于DVL大于SVL，其中SVL约等于背景水平。
