CaATPase content is lower in cardiac sarcoplasmic reticulum isolated from old rats.
CaATPase content is lower in cardiac sarcoplasmic reticulum isolated from old rats.
复制标题
从老年大鼠分离的心脏肌浆网中CaATP酶含量较低。
DOI：
10.1152/ajpheart.1993.264.5.h1609
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Tate,CA
中科院分区：
文献类型：
--
作者：
Taffet,GE;Tate,CA
从衰老的Fischer 344雄性大鼠心脏分离的肌浆网（SR）中，草酸盐促进的atp依赖性钙摄取速率，钙腺苷三磷酸酶（CaATPase），减慢了30-40%。为了确定潜在的机制，从11- 12岁（成年）和22- 24岁（衰老）雄性Fischer 344大鼠中分离心脏SR。两组间SR产率和其他膜细胞器污染率相似。衰老组匀浆和分离的SR对钙的吸收速度慢28 ~ 44% （P < 0.05）。在离体SR中，衰老组CaATPase活性计算最大速度（Vmax）随ATP或钙浓度的变化降低了20 ~ 30% (P < 0.05)；然而，CaATPase活性对钙和ATP的亲和力没有改变。衰老大鼠SR中钙依赖性磷酸酶（EP）含量降低（P < 0.05）与Vmax降低相一致。因此，酶活性与磷酸酶含量之比（Vmax/EP）各组间基本一致。衰老大鼠SR中免疫反应性caatp酶蛋白降低22 +/- 2%。综上所述，这些数据表明，老年大鼠心脏SR中钙转运缓慢的主要机制是caatp酶蛋白含量较低。
The rate of oxalate-facilitated ATP-dependent calcium uptake by the calcium pump, calcium adenosinetriphosphatase (CaATPase), is 30-40% slower in the sarcoplasmic reticulum (SR) isolated from the hearts of senescent Fischer 344 male rats. To determine the underlying mechanism, cardiac SR was isolated from 11- to 12-mo-old (adult) and 22- to 24-mo-old (senescent) male Fischer 344 rats. The yield of SR and contamination by other membrane organelles were similar between the groups. The rate of calcium uptake by the homogenate and isolated SR was 28-44% slower (P < 0.05) in the senescent group. In the isolated SR the calculated maximal velocity (Vmax) of CaATPase activity as a function of varying concentrations of ATP or calcium was 20-30% lower (P < 0.05) in the senescent group; however, the affinities for both calcium and ATP of CaATPase activity were unaltered. The lower Vmax was matched by a decreased (P < 0.05) content of calcium-dependent phosphoenzyme (EP) in the SR isolated from the senescent rats. Thus the ratio of enzyme activity to phosphoenzyme content (Vmax/EP) was similar between the groups. The immunoreactive CaATPase protein was 22 +/- 2% lower in the SR from the senescent rats. Taken together the data indicate that the major mechanism underlying the slower calcium transport by cardiac SR isolated from old rats is a lower content of the CaATPase protein.