Answers are grounded in this paper and cite their sources.
Tryptic phosphopeptides from HeLa ribosomal protein S6 have been separated by chromatography, followed by electrophoresis. Three phosphopeptides were found in S6 from cells treated in vivo with dibutyryl cAMP and at least four different phosphopeptides were found from cells treated with insulin plus the essential amino acids. Only phosphoserine was found in S6 isolated from insulin-treated cells.
No takes yet. Share an insight, caveat, or question.
Lastick et al. (1981) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: