Table 3.

Identified autophosphorylation sites of Flag-PEPR1 expressed in E.coli.

Site	Counts	Mr (expt)	Mr (calc)	Expect	Peptide
Y805*	110	2002.4556	2002.9289	8.90E−10	K.DApYVFTQEEGPSLLLNK.V
T808*	15	2002.4616	2002.9289	9.50E−10	K.DAYVFpTQEEGPSLLLNK.V
Y842*	3	951.2092	951.4328	6.10E−04	R.GAHGIVpYR.A
S848*	9	1258.3030	1258.6322	7.10E−08	R.ASLGpSGKVYAVK.R
S861*	5	1021.2626	1021.5110	9.00E−05	R.LVFApSHIR.A
S868*	1	916.1130	916.3296	1.40E−01	R.ANQpSMMR.E
Y910*	8	1450.3386	1450.6857	2.00E−06	K.GSLpYDVLHGVSPK.E

Tryptic peptides identified to contain phosphorylated residues (pS, pT, or pY) are shown in bold and sites not reported unambiguously earlier are identified with asterisks. All spectra were subject to manual verification. The experimental (expt) and calculated (calc) monisotopic masses are shown along with the expectation value reported in Mascot. The values for spectral counts for each identified peptide are the sums from three independent experiments. Oxidized methionine is identified as (ox)Met.