Table II. Mass spectrometric quantification of thylakoid protein phosphorylation from wt and stt7 cells in state 1 and state 2.

The state 2/state 1 ratios for mutant and wild type were determined in every LC-MS experiment from the areas of extracted ion chromatograms for each of the differentially labeled phosphorylated peptides corresponding to a particular protein. The m/z values are shown only for the light isotope-labeled peptide ions. The data are averages (±S.D.) from three different preparations. The state 1 and state 2 samples from each preparation were analyzed by both forward and reversed stable isotope labeling.

* The VAtSTGTR phosphopeptide signal was not detected in the stt7 sample in all three experiments.