Figure 4.

Hydrolytic stability and phosphoamino acid analysis of the phosphorylated NTHK2-KD. The NTHK2-KD was autophosphorylated in the presence of Mn²⁺ (A and C) or Ca²⁺ (B and D), and then the phosphorylated NTHK2-KD was subjected to treatments with water, HCl, or NaOH (A and B). After autoradiography, the treated protein blots were stained with Coomassie blue. The phosphorylated NTHK2-KD was further subjected to phosphoamino acid analysis (C and D). The positions of the phosphoamino acids were identified by spraying with ninhydrin (left), and the labeled residues were revealed by autoradiography (right).