人中枢神经系统髓磷脂磷酸转移酶系统的部分特性
Partial characterization of the phosphotransferase system of human central-nervous-system myelin.
作者信息
Wu N C, Yourist J E, Rector W D, Ahmad F
出版信息
Biochem J. 1983 Mar 1;209(3):789-95. doi: 10.1042/bj2090789.
The phosphotransferase system of human central-nervous-system myelin was investigated. Evidence obtained indicated the presence of at least two different phosphotransferase systems (cyclic nucleotide-dependent and -independent) in myelin, which were found to be firmly associated with the membrane. The cyclic AMP-dependent kinase of myelin and white-matter cytosol preferentially phosphorylated certain histone fractions and displayed only modest activity with basic protein as substrate. On the other hand, the cyclic nucleotide-independent system showed specificity toward basic protein. Its activity was not only dependent on Mg2+ but it was greatly enhanced by this bivalent cation. Whereas the cyclic nucleotide-dependent kinase could be extracted with buffers containing Triton X-100, the bivalent cation-regulated kinase resisted solubilization from myelin under these conditions.
对人中枢神经系统髓磷脂的磷酸转移酶系统进行了研究。所获得的证据表明，髓磷脂中存在至少两种不同的磷酸转移酶系统（环核苷酸依赖性和非依赖性），它们与膜紧密相连。髓磷脂和白质胞质溶胶中的环磷酸腺苷依赖性激酶优先使某些组蛋白组分磷酸化，而以碱性蛋白为底物时活性仅适度。另一方面，环核苷酸非依赖性系统对碱性蛋白具有特异性。其活性不仅依赖于Mg2+，而且这种二价阳离子可大大增强其活性。环核苷酸依赖性激酶可用含 Triton X-100 的缓冲液提取，而在这些条件下二价阳离子调节的激酶则难以从髓磷脂中溶解出来。
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