Figure 3.

Phosphorylation of synthetic peptides. Peptides were phosphorylated as described in the Experimental section and subjected to electrophoresis on thin-layer cellulose at pH 3.5. The position of the phosphopeptides is indicated by the arrow, the identification being based on the fact that the ninhydrin-stained material (predominantly unphosphorylated and hence with a greater positive charge) migrated just ahead of this. Lane 1 contained RRIEEYHQTTEKN, lane 2: RRIEEYHQATEKN, lane 3: RRIEEYHQTAEKN, and lane 4; no peptide.