FIG. 2.

Autoradiographs of in vitro kinase reactions. (A) Purified rSTK was incubated in kinase buffer with [γ-³²P]ATP and Mn²⁺ alone and in the presence of MBP and rSTP as indicated. Proteins were resolved by SDS-PAGE and visualized by autoradiography. Shown are representative autoradiographs. (B) Increasing amounts of purified rSTK were added to separate kinase reaction mixtures to observe the dose-dependent effect. One microgram of rSTK was used for the time course and cation dependency experiments, where minutes and cations are shown above the autoradiographs. (C) Thin-layer chromatography results showing phosphoamino acid standards stained with ninhydrin (left) and autophosphorylated rSTK hydrolysis products revealed by autoradiography (right). The first and second dimensions are indicated by arrows.