INORGANIC POLYPHOSPHATE IN MAMMALIAN-CELLS AND TISSUES
INORGANIC POLYPHOSPHATE IN MAMMALIAN-CELLS AND TISSUES
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DOI：
10.1074/jbc.270.11.5818
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发表时间：
1995-03-17
影响因子：
4.8
通讯作者：
KORNBERG, A
中科院分区：
文献类型：
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作者：
KUMBLE, KD;KORNBERG, A
无机聚磷酸盐（polyP）是由数百个正磷酸盐（Pi）残基通过高能磷酸酐键连接的线性聚合物，已经通过明确的酶方法在多种哺乳动物细胞系和组织中鉴定和测量。（0.5 pmol/100 μ g蛋白质）通过大肠杆菌多磷酸激酶将其转化为ATP来测定，或者，通过酿酒酵母外切多聚磷酸酶转化为P-i，水平为25至120 μ M在啮齿类动物组织中发现了50至800个残基长的链（就P-i残基而言）在一些实施方案中，所述蛋白质可以在细胞（脑、心脏、肾、肝和肺）和亚细胞级分（细胞核、线粒体、质膜和微粒体）中表达。脑中的聚P主要是接近800个残基，并且在出生前和出生后以相似的水平发现。通过成纤维细胞、T细胞、肾和肾上腺细胞的细胞系将P-1转化为聚P达到超过10 pmol/mg细胞蛋白/h的水平。从培养基中的P-i合成聚P绕过细胞内P-i和ATP池，表明膜组分的直接参与。在融合的PC 12（肾上腺嗜铬细胞瘤）细胞，聚P周转几乎是在一个小时内完成，而在成纤维细胞有很少的营业额在四个小时，聚P的无处不在和变化，其大小，位置和代谢是一个多功能的指示，这种聚合物在哺乳动物系统。
Inorganic polyphosphate (polyP), a linear polymer of hundreds of orthophosphate (P-i) residues linked by high-energy, phosphoanhydride bonds, has been identified and measured in a variety of mammalian cell lines and tissues by unambiguous enzyme methods, Subpicomole amounts of polyP (0.5 pmol/100 mu g of protein) were determined by its conversion to ATP by Escherichia coli polyphosphate kinase and, alternatively, to P-i by Saccharomyces cerevisiae exopolyphosphatase, Levels of 25 to 120 mu M (in terms of P-i residues), in chains 50 to 800 residues long, were found in rodent tissues (brain, heart, kidneys, liver, and lungs) and in subcellular fractions (nuclei, mitochondria, plasma membranes, and microsomes). PolyP in brain was predominantly near 800 residues and found at similar levels pre- and postnatally, Conversion of P-i into polyP by cell lines of fibroblasts, T-cells, kidney, and adrenal cells attained levels in excess of 10 pmol per mg of cell protein per h. Synthesis of polyP from P-i in the medium bypasses intracellular P-i and ATP pools suggesting the direct involvement of membrane component(s). In confluent PC12 (adrenal pheochromocytoma) cells, polyP turnover was virtually complete in an hour, whereas in fibroblasts there was little turnover in four hours, The ubiquity of polyP and variations in its size, location, and metabolism are indicative of a multiplicity of functions for this polymer in mammalian systems.