Typical location of phosphoryl groups

The addition of a phosphoryl group can occur on Serine (Ser), Threonine (Thr) and Tyrosine (Tyr) side chains via a phosphoester bond formation. 

Featured Citations

Quantitative Analysis of ATM Phosphorylation in Lymphocytes.

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From AnaSpec : Purified peptides SLAFEEGSQSTTISSLSEK(S1981) and SLAFEEG pS QSTTISSLSEK(p-S1981)

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