Figure 5From: Probing the stoichiometry of β2-adrenergic receptor phosphorylation by targeted mass spectrometry Targeted MS of phosphorylation sites S355 and S356 of β2AR: calibration curves of target peptide standards. Calibration curve of mono-phospho-peptides (A) containing pS355 (●) or pS356 (■) and non-phospho-peptide (B). For protocol, see the Materials and methods section.Back to article page