Volpe P, Damiani E, Salviati G, Margreth A
J Muscle Res Cell Motil. 1982 Jun;3(2):213-30. doi: 10.1007/BF00711943.
Early postnatal changes (4-5 days to 15 days after birth) in the biochemical composition of microsomes were investigated in rabbit skeletal muscles destined to become fast-twitch muscles. During this period, a steady decrease in the microsomal content of cholesterol and of ouabain-sensitive Na + /K + -ATPase activity, as well as a decrease in protein electrophoretic components in the 80 000-70 000 molecular weight range, were observed. These changes are probably due to a diminishing yield of microsomal membranes derived from T-tubules, as the age of the animals increases, and are indicated from a knowledge of the mixed composition of muscle microsomes and previous biochemical data on isolated T-tubules. The content of cytochrome b5, which was found to be high in muscle microsomes of newborn animals, decreased strikingly as the amount of membrane-bound Ca2 + -ATPase protein increased, with a crossing-over point at about 7-10 days after birth. These changes, possibly corresponding to a transition from precursor sarcoplasmic reticulum (SR) to mature SR, were found to be temporally correlated with changes in [3H] alpha-tocopherol binding ability of the microsomes and in the mitochondrial content of glycerol phosphate dehydrogenase. At the same critical periods, coincident with the onset of motile activity, the immunological cross-reactivity of the Ca2 + -ATPase protein of microsomal vesicles, with antibody specific for the Ca2 + -ATPase of adult fast SR, was found to increase markedly, as tested by competitive enzyme-linked immunosorbent assay (ELISA). The immunological data are consistent with data in the literature demonstrating an increase in the concentration of Ca2 + -ATPase molecules in the SR membranes during ontogenic development. Both these data and catalytic data, however, suggest that the Ca2 + -ATPase protein is present in the same form in the SR of immature and of adult fast muscle and, in an antigenically different form, in slow muscle SR.
对注定要成为快肌的兔骨骼肌微粒体生化组成的产后早期变化（出生后4 - 5天至15天）进行了研究。在此期间，观察到微粒体中胆固醇含量、哇巴因敏感的Na⁺/K⁺ - ATP酶活性稳步下降，以及分子量在80000 - 70000范围内的蛋白质电泳成分减少。这些变化可能是由于随着动物年龄的增加，源自横管的微粒体膜产量减少，这从肌肉微粒体的混合组成以及先前关于分离横管的生化数据可知。细胞色素b5的含量在新生动物的肌肉微粒体中较高，随着膜结合Ca²⁺ - ATP酶蛋白量的增加而显著下降，在出生后约7 - 10天出现交叉点。这些变化可能对应于从前体肌浆网（SR）到成熟SR的转变，发现其在时间上与微粒体的[³H]α - 生育酚结合能力以及线粒体甘油磷酸脱氢酶含量的变化相关。在相同的关键时期，与运动活动开始同时，通过竞争性酶联免疫吸附测定（ELISA）测试发现，微粒体囊泡的Ca²⁺ - ATP酶蛋白与成年快肌SR的Ca²⁺ - ATP酶特异性抗体的免疫交叉反应性显著增加。免疫数据与文献中的数据一致，表明在个体发育过程中SR膜中Ca²⁺ - ATP酶分子浓度增加。然而，这些数据和催化数据都表明，Ca²⁺ - ATP酶蛋白在未成熟和成年快肌的SR中以相同形式存在，而在慢肌SR中以抗原性不同的形式存在。
