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研究了二价金属离子(Mg2+,Ca2+,Mn2+,Zn2+)对来源于酵母"Y.Lipolytica"(wildW-29)的一种蛋白质激酶酪蛋白激酶I(CK-I)活性的影响。发现,CK-I的催化活性依赖于Mg2+的作用,而不受Ca2+的调节;Zn2+是CK-I的抑制剂(I0.5≈250μmol/L).若反应中存在饱和浓度的Mg2+(10mmol/L),Mn2+(<50μmol/L)既对CK-II有激活作用,又有抑制作用;而且,若Mg2+不存在,Mn2+则是CK-I的激活剂。尤其是,发现Mg2+,Mn2+对CK-I活性的调节作用不同,CK-I对底物中靶氨基酸的磷酸化作用就不同。当反应中存在Mg2+(10mmol/L)而无Mn2+时,靶氨基酸主要是丝氨酸(Serine)和苏氨酸(Threonine),其各占被磷酸化总量的61%和32%,且只有极微量的酪氨酸(Tyrosines)被磷酸化;当反应中仅存在Mn2+(10mmol/L)而无Mg2+时,靶氨基酸主要是丝氨酸、苏氨酸和酪氨酸,其各占被磷酸化总量的42%,41%和15%.还发现CK-I能对合成的“聚Glu-Tyr”磷酸化。这是在CK-I研究史上首次发现酪氨酸也?
The effect of divalent metal ions (Mg2 +, Ca2 +, Mn2 +, Zn2 +) on the activity of a protein kinase casein kinase I (CK-I) derived from the yeast “Y.Lipolytica” (wild W-29) was studied. It was found that the catalytic activity of CK-I depended on the action of Mg2 + and not on the regulation of Ca2 +; Zn2 + was an inhibitor of CK-I (I0.5≈250 μmol / L). If the concentration of Mg2 + (10mmol / L) and Mn2 + (<50μmol / L) in the reaction are both active and inhibitory for CK-II, and if Mg2 + is not present, Mn2 + Agent. In particular, it was found that the regulatory effects of Mg2 + and Mn2 + on CK-I activity are different, and the phosphorylation of target amino acids in the substrate by CK-I is different. When Mg2 + (10 mmol / L) and Mn2 + were present in the reaction, the target amino acids were mainly Serine and Threonine, which each accounted for 61% and 32% of the total phosphorylated, with only a very small amount Tyrosines were phosphorylated. When there was only Mn2 + (10 mmol / L) but no Mg2 + in the reaction, the target amino acids were mainly serine, threonine and tyrosine, each of which accounted for the total phosphorylated 42%, 41% and 15%. It was also found that CK-I phosphorylates the synthetic “poly Glu-Tyr”. This is the first time in the history of CK-I found that tyrosine also?