Effect of metal ions on the activity of cascein kinase II from Xenopus laevis

• Published in: FEBS letters 1993-01, Vol.315 (2), p.173-177
• Main Authors: Gatica, Marta, Hinrichs, María V., Jedlicki, Ana, Allende, Catherine C., Allende, Jorge E.
• Format: Article
• Language: English
• Subjects: CaScin kinase II; CaScin kinase II α and β subunits; Divalent metal ion; Xenopus laevis
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(93)81157-U

CaSein kinase II purified from the nuclei of Xenopus laevis oocytes as well as the recombinant α and β 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 Mg 2+, Mn 2+, or Co 2+. Optimal concentrations were 7–10 mM for Mg 2+, 0.5–0.7 mM for Mn 2+ and 1–2 mM for Co 2+. In the presence of Mn 2+ or Co 2+ the enzyme used GTP more efficiently than ATP as a phosphate donor while the reverse was true in the presence ofMg 2+. The apparent K m values for both nucleotide triphosphates were greatly decreased in the presence of Mn 2+ as compared with Mg 2+. Addition of Zn 2+ (above 150 μM) to an assay containing the optimal Mg 2+ ion concentration caused strong inhibition of both holoenzyme and α subunit. Inhibition of the holoenzyme by 400 μM Ni 2+ could be reversed by high concentrations of Mg 2+ but no reversal of this inhibition was observed with the α subunit.