. Author manuscript; available in PMC: 2014 Jan 6.

Published in final edited form as: Diabetologia. 2011 Aug 18;54(11):10.1007/s00125-011-2271-9. doi: 10.1007/s00125-011-2271-9

Table 2. IRS-1 fragment ions for quantification.

Start	Stop	Peptide sequence	Phosphorylation site	MS2 or MS3?	Product ion (charge state)	Mass
303	325	SRTESITATSPASMVGGKPGSFR	Ser303	MS3	y21 (+2)	1,049.02
			Ser307	x	x	x
			Ser312	x	x	x
			Ser323	MS3	b14 (+1)	1,436.67
					y9 (+1)	886.49
328	353	ASSDGEGTMSRPASVDGSPVSPSTNR	Ser330	MS2	y20 (+2)	1,009.98
				MS2	y22 (+2)	1,103.01
				MS2	y11 (+1)	1,116.53
			Ser348	MS2	y8 (+1)	937.41
				MS2	y20 (+2)	1,049.96
				MS2	b11 (+1)	1,095.44
444	457	SVTPDSLGHTPPAR	Thr446	MS3	y9 (+1)	935.51
				MS3	y10 (+1)	1,050.53
				MS3	y11 (+1)	1,147.59
494	520	CTPGTGLGTSPALAGDEAASAADLDNR	Thr495	MS2	y14 (+1)	1,375.61
					y17 (+1)	1,656.78
					y18 (+1)	1,743.81
525	538	THSAGTSPTITHQK	Ser527	MS3	y11 (+1)	1,140.60
			Ser531	MS3	y11 (+1)	1,122.59
573	580	HSAFVPTR	Ser574	x	x	x
596	626	GGHHRPDSSTLHTDDGYMPMSPGVAPVPSGR	Ser616	x	x	x
627	638	KGSGDYMPMSPK	Ser629	MS3	[M+2H-98-64]	624.29^a
			ser636	MS3	[M+2H-98-64]²⁺	624.29^a
892	922	SPGEYVNIEFGSDQSGYLSGPVAFHSSPSVR	Ser892	x	x	x
999	1016	QSYVDTSPAAPVSYADMR	Ser1005	MS2	y11 (+1)	1,193.56
1075	1081	VNLSPNR	Ser1078	MS3	y5 (+1)	568.32
					y6 (+1)	682.36
1098	1112	RHSSETFSSTPSATR	Ser1100	MS3	y12 (+1)	1,270.59
1099	1112	HSSETFSSTPSATR	Ser1101	MS3	b8 (+1)	845.34
					y10 (+1)	1,054.52
1141	1161	HSSASFENVWLRPGELGGAPK	Ser1142	MS3	y11 (+1)	1,183.559
					y19 (+2)	1,008.02
					y18 (+2)	964.50
					y17 (+2)	928.99
			Ser1143	x	x	x
			Ser1145	MS3	y19 (+2)	999.02
					y18 (+2)	955.50
1221	1236	RSSEDLSAYASISFQK	Ser1222	x	x	x
					x	x
			Ser1223	x	x	x

The highest fragment ion in the MS3 spectrum, loss of phosphoric acid (98 Da) and SOCH₄ (64 Da) from the parent ion. Peptides containing pSer629 and pSer636 were resolved by HPLC