PHOSVITIN KINASE FROM BRAIN - ACTIVATION BY IONS + SUBCELLULAR DISTRIBUTION
PHOSVITIN KINASE FROM BRAIN - ACTIVATION BY IONS + SUBCELLULAR DISTRIBUTION
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DOI：
10.1042/bj0930084
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发表时间：
1964-01-01
影响因子：
4.1
通讯作者：
LAVIN, BE
中科院分区：
文献类型：
--
作者：
RODNIGHT, R;LAVIN, BE
从牛脑灰质中制备的Mg 2+离子依赖性的胰高血糖素激酶被各种单价阳离子进一步激活。在200 m[image]浓度下，K+是最有效的阳离子，但Na+，Rb+，Cs+和NH 4+离子的效果略差。胆碱和三羟甲基氨基甲烷也刺激酶系统，但Li+离子完全没有影响。一价阳离子的刺激百分比明显依赖于存在的Mg 2+离子的浓度：例如，在1 m[image]-MgCl 2，200 m[image]-KCl使活性增加约8倍，而在5 m[image]-MgCl 2（不存在一价阳离子时的最佳Mg 2+离子浓度）刺激仅为2倍。以前的报道，这种酶是由磷酸根离子刺激没有得到证实。GTP在向阿托伐他汀提供磷酸盐方面与ATP大致一样有效。该酶存在于细胞核、线粒体、微粒体和可溶性蛋白组分中。无论是总活性还是单位蛋白量的活性，可溶性蛋白都是最高的。Na+和K+离子对酶的可溶性部分的效果进行了比较，其对微粒体酶的效果：在这两种情况下，发现近似相等的刺激。
The Mg2+ ion-dependent phosvitin kinase prepared from ox-brain grey matter was further activated by a variety of univalent cations. At 200 m[image] concentration, K+ was the most effective cation, but Na+, Rb+, Cs+ and NH4+ ions were only slightly less effective. Choline and tris also stimulated the enzyme system, but Li+ ions were altogether without effect. The percentage stimulation by univalent cations was markedly dependent on the concentration of Mg2+ ions present: for instance, at 1 m[image]-MgCl2, 200 m[image]-KCl increased activity approximately eightfold, whereas at 5 m[image]-Mg Cl2 (the optimum Mg2+ ion concentration in the absence of univalent cation) stimulation was only twofold. Previous reports that this enzyme is stimulated by phosphate ions were not confirmed. GTP was approximately as effective as ATP in donating phosphate to phosvitin. The enzyme was present in the nuclear, mitochon-drial, microsomal and soluble protein fractions of the cell. Both in total activity and activity per unit quantity of protein the soluble proteins were highest. The effect of Na+ and K+ ions on the enzyme of the soluble fraction was compared with their effect on the microsomal enzyme: approximately equal stimulation was found in both cases.