POLYPHOSPHOINOSITIDES IN MYELIN
POLYPHOSPHOINOSITIDES IN MYELIN
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DOI：
10.1042/bj0960644
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发表时间：
1965-01-01
影响因子：
4.1
通讯作者：
DAWSON, RMC
中科院分区：
文献类型：
--
作者：
EICHBERG, J;DAWSON, RMC
通过差速离心和密度梯度离心对豚鼠前脑匀浆进行分级分离时，大多数多磷酸肌醇磷脂在富含髓磷脂的颗粒中被回收。纯髓磷脂制剂中的磷脂所含的二磷酸肌醇磷脂和三磷酸肌醇磷脂的比例比全脑磷脂中的比例高2 - 3倍。在髓鞘形成期间，二磷酸肌醇磷脂和三磷酸肌醇磷脂出现在幼鼠大脑中。给豚鼠注射[³²P]磷酸盐后，分离出的纯髓磷脂中多磷酸肌醇磷脂的标记量与全脑一样多，而其他髓磷脂磷脂的合成很少。当脑亚细胞组分与[γ - ³²P]ATP一起孵育时，富含髓磷脂的组分中出现了一些三磷酸肌醇磷脂标记，而二磷酸肌醇磷脂的活跃标记主要位于线粒体组分中。所存在的Na⁺、K⁺以及Mg²⁺和Ca²⁺含量与多磷酸肌醇磷脂显示出紧密的酸碱当量关系。结论是二磷酸肌醇磷脂和三磷酸肌醇磷脂是髓鞘或紧密相关结构中代谢迅速的成分。
On fractionation of guinea-pig forebrain homogenates by differential and gradient-density centrifugation most of the polyphosphoinositides were recovered in the myelin-rich particles. The phospholipids of pure preparations of myelin contained di- and tri-phosphoinositide in proportions 2-3 times greater than in the whole-brain phospholipids. Di- and triphosphoinositide appeared in young rat brain during the period of myelination. After the administration of [32p] phosphate to guinea pigs the labelling of the polyphosphoinositides in isolated pure myelin was as great as in the whole brain, whereas little synthesis of the other myelin phospholipids had occurred. When brain subcellular fractions were incubated with [gamma-32p]ATP, some triphosphoinositide labelling occurred in the myelin-rich fraction whereas the active labelling of diphosphoinositide was localized mainly in the mitochondrial fraction. The Na+, K+ and Mg2+ plus Ca2+ content present showed close acid-base equivalence to the polyphosphoinositides. It is concluded that di- and tri-phosphoinositide are rapidly-metabolizing components of the myelin sheath or intimately associated structures.