Intracellular compartmentalization of adenosine triphosphate.
Intracellular compartmentalization of adenosine triphosphate.
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DOI：
10.1016/s0021-9258(18)66958-3
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发表时间：
1986-10
期刊：
影响因子：
--
通讯作者：
D. Miller;S. B. Horowitz
中科院分区：
文献类型：
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作者：
D. Miller;S. B. Horowitz
采用低温显微解剖方法，研究了三磷酸腺苷（ATP）在冷库蛙卵母细胞内的分布和扩散。我们测量了细胞核、动物和植物半球细胞质以及细胞内参比相（iRP，一种微注射明胶“细胞器”）中的ATP浓度。区域浓度不相等：细胞核比动物卵浆大得多，比植物卵浆大得多。通过绘制核和细胞质ATP浓度作为参考相ATP浓度的函数（等温分析）来确定ATP结合和水的可用性（作为溶剂）。ATP的核/iRP等温线为等摩尔线，表明核质在溶剂性质上类似于iRP明胶（因此是一种简单的水溶液）。细胞质/iRP等温线更为复杂，其斜率远小于图原点上方的统一和有序截距。它们证明细胞质中存在能够排除和结合ATP的机制。这些机制是导致atp细胞内分布不均匀的原因。此外，排斥和结合对细胞“可溶空间”中的ATP浓度有不同的和相反的影响，从而影响ATP进入细胞反应的可用性。因此，在试图模拟atp在新陈代谢中的作用时，必须考虑这些现象。
The intracellular distribution and diffusivity of adenosine triphosphate (ATP) was studied by cryomicrodissection of individual Rana pipiens oocytes. We measured ATP concentrations in the nucleus, in animal and vegetal hemisphere cytoplasm, and in an intracellular reference phase (iRP, a microinjected gelatin "organelle") which samples diffusive ATP. Regional concentrations were not equal: nucleus much greater than animal ooplasm greater than vegetal ooplasm. ATP binding and water availability (as solvent) were determined by plotting nuclear and cytoplasmic ATP concentrations as a function of reference phase ATP concentrations (isothermal analysis). The nucleus/iRP isotherm for ATP was an equimolar line, showing that nucleoplasm resembles iRP gelatin (and consequently a simple aqueous solution) in its solvent properties. Cytoplasm/iRP isotherms were more complex, having slopes much less than unity and ordinal intercepts above the graph's origin. They demonstrate the presence in cytoplasm of mechanisms that are capable of excluding and binding ATP. These mechanisms are responsible for the inhomogeneity in ATPs intracellular distribution. In addition, exclusion and binding have different and opposing effects on ATP concentrations in the cell's "soluble space," and hence on ATP availability to enter into cellular reactions. It follows that these phenomena must be considered in attempts to model ATPs role in metabolism.