EFFECT OF METAL-IONS ON THE ACTIVITY OF CASEIN KINASE-II FROM XENOPUS-LAEVIS
EFFECT OF METAL-IONS ON THE ACTIVITY OF CASEIN KINASE-II FROM XENOPUS-LAEVIS
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DOI：
10.1016/0014-5793(93)81157-u
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发表时间：
1993-01-04
期刊：
影响因子：
3.5
通讯作者：
ALLENDE, JE
中科院分区：
文献类型：
--
作者：
GATICA, M;HINRICHS, MV;ALLENDE, JE
用不同的二价金属离子对从非洲爪哇卵母细胞核中纯化的酪蛋白激酶II和从克隆的基因中产生的重组非洲爪哇沙门氏菌CKII的α、β亚基进行了检测。这两种来源的酶对Mg2+、Mn2+或Co2+都有活性。最佳浓度为：镁离子7-10 mM，锰离子0.5-0.7 mM，Co2+1-2 mM。在Mn2+或Co2+存在下，该酶利用GTP作为磷酸供体的效率高于ATP，而在Mg2+存在下则相反。与Mg~(2+)相比，在Mn~(2+)存在下，两种核苷酸三磷酸盐的表观K(M)值都大大降低。在含有最佳镁离子浓度的测定中加入锌离子(150微米以上)，对全酶和一个亚基都有强烈的抑制作用。400umNi2+对全酶的抑制作用可被高浓度的镁离子逆转，但这种抑制作用不能被α亚基逆转。
Casein kinase II purified from the nuclei of Xenopus laevis oocytes as well as the recombinant alpha and beta subunits of the X. laevis CKII, produced in E coli from the cloned cDNA genes, were tested with different divalent metal ions. The enzyme from both sources was active with either Mg2+, Mn2+, or Co2+. Optimal concentrations were 7-10 mM for Mg2+, 0.5-0.7 mM for Mn2+ and 1-2 mM for Co2+. In the presence of Mn2+ or Co2+ the enzyme used GTP more efficiently than ATP as a phosphate donor while the reverse was true in the presence of Mg2+. The apparent K(m) values for both nucleotide triphosphates were greatly decreased in the presence of Mn'' as compared with Mg2+. Addition of Zn2+ (above 150 muM) to an assay containing the optimal Mg2+ ion concentration caused strong inhibition of both holoenzyme and a subunit. Inhibition of the holoenzyme by 400 muM Ni2+ could be reversed by high concentrations of Mg2+ but no reversal of this inhibition was observed with the alpha subunit.