. Author manuscript; available in PMC: 2010 Nov 16.

Published in final edited form as: J Am Soc Mass Spectrom. 2010 Jun 19;21(10):1649–1659. doi: 10.1016/j.jasms.2010.06.005

Table 1.

Number of Times Specific Phosphorylation Sites Were Observed by MALDI/MS From Four Independent MOAC Enrichments.

Tryptic Peptide	Theoretical [M+H]+	Amino Acid Sequence	Phosphorylated Residue(s)	IMAC^a Fe-NTA	Titansphere TiO₂ CRC	Glygen NuTip			Phos-Trap TiO₂ Kit
Tryptic Peptide	Theoretical [M+H]+	Amino Acid Sequence	Phosphorylated Residue(s)	IMAC^a Fe-NTA	Titansphere TiO₂ CRC	TiO₂	ZrO₂	TiO₂/ZrO₂	Phos-Trap TiO₂ Kit

α_S1 T15/T14-15	1660.79 / 1951.95	(YK)¹⁰⁶VPQLEIVPNpSAEER¹¹⁹	Ser 115	X	4	4	4	4	4
α_S1 T7^b	1927.69	⁴³DIGpSEpSTEDQAMEDIK⁵⁸	Ser 46,48	X	4	4	4	4	4
α_S1 T8	2720.91	⁵⁹QMEAEpSIpSpSpSEEIVPNpSVEQK⁷⁹	Ser 64,66,67,68,75	X	2	4	4	2	2
α_S1 T6-7	2678.02	³⁷VNELpSKDIGpSEpSTEDQAMEDIK⁵⁸	Ser 41,46,48		0	3	3	2	2

α_S2 T14/T14-15	1411.50 / 1539.60	¹²⁶EQLpSTpSEENSKK¹³⁶(K)	Ser 129,131		0	3	2	0	1
α_S2 T16^b/T15-16,T16-17	1466.61 / 1594.71	(K)¹³⁸TVDMEpSTEVFTK¹⁴⁹(K)	Ser 143	X	2	4	4	4	4
α_S2 T2/T1-2	2618.91 / 2747.00	(K)²NTMEHVpSpSpSEESIIpSQETYK²¹	Ser 8,9,10,16	X	1	4	4	0	2
α_S2 T7	3008.03	⁴⁶NANEEEYSIGpSpSpSEEpSAEVATEEVK⁷	Ser 56, 57, 58, 61	X	1	4	3	2	2

β T6/T5-6	2061.83 / 2432.05	(IEK)³³FQpSEEQQQTEDELQDK⁴⁸	Ser 35	X	4	4	4	4	4
β T2 / T1-2	2966.17 / 3122.27	(R)²ELEELNVPGEIVEpSLpSpSpSEESITR²⁵	Ser 15,17,18,19		4	4	4	4	4

# of Unique Sites of Phosphorylation Observed in 4 of 4 MOAC enrichments					8	22	17	9	9

Results from a single IMAC enrichment

Observed as both native and oxidized by MALDI/MS