Figs shows the effect of Mn2+-Phos-tag on the mobility of phosphorylated proteins (α-casein, β-casein, and ovalbumin) in SDS-PAGE . In the absence of Mn2+-Phos-tag (i.e. normal SDSPAGE),
the mobilities of phosphorylated and dephosphorylated proteins are almost the same. In the presence of Mn2+-Phos-tag (50, 100, and 150 M), a difference in mobility between the phosphorylated and the corresponding dephosphorylated proteins is observed. The Phos-tag ligand without Mn2+ did not show any mobility shifts of phosphorylated proteins (data not shown). The Rf values of all samples become smaller dose-dependently. This is possibly due to electrostatic interaction between cationic Mn2+-Phos-tag and an-ionic SDS-bound proteins. Interestingly β-casein (5P) appears as eight bands using 100 M Mn2+-Phos-tag, indicating
the existence of at least eight isotypes with a different number of phosphomonoester dianions.
Kinoshita, E., Kinoshita-Kikuta, E., Takiyama, K., and Koike, T.
|Composition of gel||