The integration of mitochondrial calcium transport and storage
The integration of mitochondrial calcium transport and storage
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DOI：
10.1023/b:jobb.0000041753.52832.f3
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发表时间：
2004-08-01
影响因子：
3
通讯作者：
Chalmers, S
中科院分区：
文献类型：
--
作者：
Nicholls, DG;Chalmers, S
分离的线粒体积累Ca2+的非凡能力已经建立了超过40年。独立摄取和外排途径的独特动力学解释了运输过程的双重功能，既可以调节基质游离Ca2+浓度，也可以在磷酸盐存在下作为大量Ca2+的临时储存。一个谜题是基质磷酸钙复合物的性质，因为在磷酸盐存在的情况下，基质游离Ca2+似乎在1-5 muM区域被缓冲，而毫摩尔Ca2+在体外培养基中仍然可溶。关键似乎是升高的基质pH和PO43-浓度与pH的三次方关系。考虑到这一点，我们现在可能最终有一个模型来解释生理线粒体Ca2+运输的主要特征。
The extraordinary capacity of isolated mitochondria to accumulate Ca2+ has been established for more than 40 years. The distinct kinetics of the independent uptake and efflux pathways accounts for the dual functionality of the transport process to either modulate matrix free Ca2+ concentrations or to act as temporary stores of large amounts of Ca2+ in the presence of phosphate. One puzzle has been the nature of the matrix calcium phosphate complex, since matrix free Ca2+ seems to be buffered in the region of 1-5 muM in the presence of phosphate while millimolar Ca2+ remains soluble in in vitro media. The key seems to be the elevated matrix pH and the third-power relationship of the PO43- concentration with pH. Taking this into account we may now finally have a model that explains the major features of physiological mitochondrial Ca2+ transport.