Advances in phosphopeptide enrichment techniques for phosphoproteomics

Amino Acids

Volumn 43, Issue 3, 2012, Pages 1009-1024

  Beltran, Luisa ^a   Cutillas, Pedro R ^a  

^a QUEEN MARY UNIVERSITY OF LONDON   (United Kingdom)

Author keywords

Cell signaling; Mass spectrometry; Proteomics; Systems biology

Indexed keywords

FORMIC ACID; PHOSPHOPEPTIDE; PHOSPHOPROTEIN; SERINE; THREONINE; TITANIUM DIOXIDE; TRIFLUOROACETIC ACID; TYROSINE; ZIRCONIUM OXIDE;

ANTIBODY AFFINITY; CATION EXCHANGE; DERIVATIZATION; ELUTION; ENRICHMENT CULTURE; HIGH PERFORMANCE LIQUID CHROMATOGRAPHY; HUMAN; HYDROPHILIC INTERACTION CHROMATOGRAPHY; HYDROPHILICITY; IMMOBILIZED METAL AFFINITY CHROMATOGRAPHY; IMMUNOAFFINITY CHROMATOGRAPHY; IMMUNOHISTOCHEMISTRY; IMMUNOPRECIPITATION; LIQUID CHROMATOGRAPHY; MASS SPECTROMETER; MATRIX ASSISTED LASER DESORPTION IONIZATION TIME OF FLIGHT MASS SPECTROMETRY; PHOSPHOPROTEOMICS; PRIORITY JOURNAL; PROTEIN CONFORMATION; PROTEIN DEGRADATION; PROTEIN PHOSPHORYLATION; PROTEIN PROCESSING; PROTEIN SECONDARY STRUCTURE; PROTEOMICS; REVERSED PHASE LIQUID CHROMATOGRAPHY; REVIEW; SIGNAL TRANSDUCTION; SYSTEMS BIOLOGY; TANDEM MASS SPECTROMETRY;

ANIMALS; CHROMATOGRAPHY, LIQUID; HUMANS; MASS SPECTROMETRY; PEPTIDE FRAGMENTS; PHOSPHOPROTEINS; PHOSPHORYLATION; PROTEIN PROCESSING, POST-TRANSLATIONAL; PROTEOME; PROTEOMICS;

EID: 84867041794     PISSN: 09394451     EISSN: 14382199     Source Type: Journal    
DOI: 10.1007/s00726-012-1288-9     Document Type: Review

References (93)

1. Adamczyk M, Gebler JC, Wu J (2001) Selective analysis of phosphopeptides within a protein mixture by chemical modification, reversible biotinylation and mass spectrometry. Rapid Commun Mass Spectrom 15:1481-1488 (Pubitemid 32786416)
2. Ahmed FE (2009) Sample preparation and fractionation for proteome analysis and cancer biomarker discovery by mass spectrometry. J Sep Sci 32:771-798
3. Ahn YH, Park EJ, Cho K, Kim JY, Ha SH, Ryu SH, Yoo JS (2004) Dynamic identification of phosphopeptides using immobilized metal ion affinity chromatography enrichment, subsequent partial b-elimination/chemical tagging and matrix-assisted laser desorption/ionization mass spectrometric analysis. Rapid Commun Mass Spectrom 18:2495-2501 (Pubitemid 39361790)
4. Alcolea MP, Cutillas PR (2010) In-depth analysis of protein phosphorylation by multidimensional ion exchange chromatography and mass spectrometry. Methods Mol Biol 658:111-126
5. Alcolea MP, Kleiner O, Cutillas PR (2009) Increased confidence in large-scale phosphoproteomics data by complementary mass spectrometric techniques and matching of phosphopeptide data sets. J Proteome Res 8:3808-3815
6. Anguenot R, Yelle S, Nguyen-Quoc B (1999) Purification of tomato sucrose synthase phosphorylated isoforms by Fe(III)-immobilized metal affinity chromatography. Arch Biochem Biophys 365:163-169 (Pubitemid 29394262)
7. Aryal UK, Ross ARS (2009) Enrichment and analysis of phosphopeptides under different experimental conditions using titanium dioxide affinity chromatography and mass spectrometry. Rapid Commun Mass Spectrom 24:219-231
8. Aryal UK, Olson DJH, Ross ARS (2008) Optimization of immobilized gallium (III) ion affinity chromatography for selective binding and recovery of phosphopeptides from protein digests. J Biomol Tech 19:296-310
9. Barford D, Das AK, Egloff M-P (1998) The structure and mechanism of protein phosphatases: insights into catalysis and regulation. Annu Rev Biophys Biomol Struct 27:133-164 (Pubitemid 28286012)
10. Barnouin KN, Hart SR, Thompson AJ, Okuyama M, Waterfield M, Cramer R (2005) Enhanced phosphopeptide isolation by Fe(III)- IMAC using 1,1,1,3,3,3-hexafluoroisopropanol. Proteomics 5:4376-4388 (Pubitemid 41739916)
11. Beausoleil SA, Jedrychowski M, Schwartz D, Elias JE, Villen J, Li J, Cohn MA, Cantley LC, Gygi SP (2004) Large-scale characterization of HeLa cell nuclear phosphoproteins. Proc Nat Acad Sci USA 101:12130-12135 (Pubitemid 39145408)
12. Blagoev B, Ong S-E, Kratchmarova I, Mann M (2004) Temporal analysis of phosphotyrosine-dependent signaling networks by quantitative proteomics. Nat Biotechnol 22:1139-1145 (Pubitemid 39166852)
13. Bodenmiller B, Mueller LN, Mueller M, Domon B, Aebersold R (2007) Reproducible isolation of distinct, overlapping segments of the phosphoproteome. Nat Methods 4:231-237 (Pubitemid 46358873)
14. Boersema PJ, Mohammed S, Heck AJR (2009) Phosphopeptide fragmentation and analysis by mass spectrometry. J Mass Spectrom 44:861-878
15. Cañas B, Piñeiro C, Calvo E, López-Ferrer D, Gallardo JM (2007) Trends in sample preparation for classical and second generation proteomics. J Chromatogr A 1153:235-258 (Pubitemid 46755189)
16. Cantin GT, Yi W, Lu B, Park SK, Xu T, Lee J-D, Yates JR (2008) Combining protein-based IMAC, peptide-based IMAC, and MudPIT for efficient phosphoproteomic analysis. J Proteome Res 7:1346-1351
17. Casado P, Cutillas PR (2011) A self-validating quantitative mass spectrometry method for assessing the accuracy of high-content phosphoproteomic experiments. Mol Cell Proteomics 10(1): M110.003079
18. Chi A, Huttenhower C, Geer LY, Coon JJ, Syka JEP, Bai DL, Shabanowitz J, Burke DJ, Troyanskaya OG, Hunt DF (2007) Analysis of phosphorylation sites on proteins from Saccharomyces cerevisiae by electron transfer dissociation (ETD) mass spectrometry. Proc Nat Acad Sci 104:2193-2198 (Pubitemid 46391374)
19. Choudhary C, Olsen JV, Brandts C, Cox J, Reddy PNG, Böhmer FD, Gerke V, Schmidt-Arras D-E, Berdel WE, Müller-Tidow C et al (2009) Mislocalized activation of oncogenic RTKs switches downstream signaling outcomes. Mol Cell 36:326-339
20. Cohen P (2001) The role of protein phosphorylation in human health and disease. Eur J Biochem 268:5001-5010
21. Cutillas PR, Jorgensen C (2011) Biological signalling activity measurements using mass spectrometry. Biochem J 434:189-199
22. Cutillas PR, Timms JF (2010) Approaches and applications of quantitative LC-MS for proteomics and activitomics. Methods Mol Biol 658:3-17
23. Cutillas PR, Geering B, Waterfield MD, Vanhaesebroeck B (2005) Quantification of gel-separated proteins and their phosphorylation sites by LC-MS using unlabeled internal standards. Mol Cell Proteomics 4:1038-1051 (Pubitemid 41223364)
24. Dai J, Jin W-H, Sheng Q-H, Shieh C-H, Wu J-R, Zeng R (2006) Protein phosphorylation and expression profiling by Yin-Yang multidimensional liquid chromatography (Yin-Yang MDLC) mass spectrometry. J Proteome Res 6:250-262
25. Dai J, Wang L-S, Wu Y-B, Sheng Q-H, Wu J-R, Shieh C-H, Zeng R (2008) Fully automatic separation and identification of phosphopeptides by continuous ph-gradient anion exchange online coupled with reversed-phase liquid chromatography mass spectrometry. J Proteome Res 8:133-141
26. De Corte V, Demol H, Goethals M, Van Damme J, Gettemans J, Vandekerckhove J (1999) Identification of Tyr438 as the major in vitro c-Src phosphorylation site in human gelsolin: a mass spectrometric approach. Protein Sci 8:234-241 (Pubitemid 29035536)
27. Dong M, Wu M, Wang F, Qin H, Han G, Dong J, Wu RA, Ye M, Liu Z, Zou H (2010) Coupling strong anion-exchange monolithic capillary with MALDI-TOF MS for sensitive detection of phosphopeptides in protein digest. Anal Chem 82:2907-2915
28. Eriksson A, Bergquist J, Edwards K, Hagfeldt A, Malmstrom D, Agmo Hernandez V (2010) Optimized protocol for on-target phosphopeptide enrichment prior to matrix-assisted laser desorption- ionization mass spectrometry using mesoporous titanium dioxide. Anal Chem 82:4577-4583
29. Feng S, Ye M, Zhou H, Jiang X, Jiang X, Zou H, Gong B (2007) Immobilized zirconium ion affinity chromatography for specific enrichment of phosphopeptides in phosphoproteome analysis. Mol Cell Proteomics 6:1656-1665 (Pubitemid 47506174)
30. Ficarro SB, McCleland ML, Stukenberg PT, Burke DJ, Ross MM, Shabanowitz J, Hunt DF, White FM (2002) Phosphoproteome analysis by mass spectrometry and its application to Saccharomyces cerevisiae. Nat Biotechnol 20:301-305 (Pubitemid 34205425)
31. Gaberc-Porekar V, Menart V (2001) Perspectives of immobilized-metal affinity chromatography. J Biochem BiophysMethods 49:335-360 (Pubitemid 33022558)
32. Gao J, Thelen JJ, Dunker AK, Xu D (2010) Musite, a tool for global prediction of general and kinase-specific phosphorylation sites. Mol Cell Proteomics 9:2586-2600
33. Gates MB, Tomer KB, Deterding LJ (2010) Comparison of metal and metal oxide media for phosphopeptide enrichment prior to mass spectrometric analyses. J Am Soc Mass Spectrom 21:1649-1659
34. Gilar M, Olivova P, Daly AE, Gebler JC (2005) Orthogonality of separation in two-dimensional liquid chromatography. Anal Chem 77:6426-6434 (Pubitemid 41436983)
35. Goshe MB, Veenstra TD, Panisko EA, Conrads TP, Angell NH, Smith RD (2001) Phosphoprotein isotope-coded affinity tags: application to the enrichment and identification of low-abundance phosphoproteins. Anal Chem 74:607-616 (Pubitemid 34131511)
36. Gronborg M, Kristiansen TZ, Stensballe A, Andersen JS, Ohara O, Mann M, Jensen ON, Pandey A (2002) A mass spectrometrybased proteomic approach for identification of serine/threoninephosphorylated proteins by enrichment with phospho-specific antibodies. Mol Cell Proteomics 1:517-527
37. Gruhler A, Olsen JV, Mohammed S, Mortensen P, Faergeman NJ, Mann M, Jensen ON (2005) Quantitative phosphoproteomics applied to the yeast pheromone signaling pathway. Mol Cell Proteomics 4:310-327 (Pubitemid 40439774)
38. Han G, Ye M, Zhou H, Jiang X, Feng S, Jiang X, Tian R, Wan D, Zou H, Gu J (2008) Large-scale phosphoproteome analysis of human liver tissue by enrichment and fractionation of phosphopeptides with strong anion exchange chromatography. Proteomics 8:1346-1361 (Pubitemid 351518547)
39. Harsha HC, Pandey A (2010) Phosphoproteomics in cancer. Mol Oncol 4:482-495
40. Hart SR, Waterfield MD, Burlingame AL, Cramer R (2002) Factors governing the solubilization of phosphopeptides retained on ferric NTA IMAC beads and their analysis by MALDI TOFMS. J Am Soc Mass Spectrom 13:1042-1051 (Pubitemid 36871599)
41. Kalo MS, Pasquale EB (1999) Multiple in vivo tyrosine phosphorylation sites in EphB receptors. Biochemistry 38:14396-14408
42. Kinoshita E, Yamada A, Takeda H, Kinoshita-Kikuta E, Koike T (2005) Novel immobilized zinc(II) affinity chromatography for phosphopeptides and phosphorylated proteins. J Sep Sci 28:155-162 (Pubitemid 40360925)
43. Larsen MR, Graham ME, Robinson PJ, Roepstorff P (2004) Improved detection of hydrophilic phosphopeptides using graphite powder microcolumns and mass spectrometry. Mol Cell Proteomics 3:456-465 (Pubitemid 38714287)
44. Larsen MR, Thingholm TE, Jensen ON, Roepstorff P, Jorgensen TJD (2005) Highly selective enrichment of phosphorylated peptides from peptide mixtures using titanium dioxide microcolumns. Mol Cell Proteomics 4:873-886 (Pubitemid 41309146)
45. Li S, Dass C (1999) Iron(III)-immobilized metal ion affinity chromatography and mass spectrometry for the purification and characterization of synthetic phosphopeptides. Anal Biochem 270:9-14 (Pubitemid 29230714)
46. Li Q-R, Ning Z-B, Tang J-S, Nie S, Zeng R (2009a) Effect of peptideto- TiO2 beads ratio on phosphopeptide enrichment selectivity. J Proteome Res 8:5375-5381
47. Li Y, Luo Y, Wu S, Gao Y, Liu Y, Zheng D (2009b) Nucleic acids in protein samples interfere with phosphopeptide identification by immobilized-metal-ion affinity chromatography and mass spectrometry. Mol Biotechnol 43:59-66
48. Lim KB, Kassel DB (2006) Phosphopeptides enrichment using online two-dimensional strong cation exchange followed by reversed-phase liquid chromatography/mass spectrometry. Anal Biochem 354:213-219
49. Link AJ, Eng J, Schieltz DM, Carmack E, Mize GJ, Morris DR, Garvik BM, Yates JR (1999) Direct analysis of protein complexes using mass spectrometry. Nat Biotechnol 17:676-682 (Pubitemid 29316146)
50. Macek B, Mann M, Olsen JV (2009) Global and site-specific quantitative phosphoproteomics: principles and applications. Annu Rev Pharmacol Toxicol 49:199-221
51. Mamone G, Picariello G, Ferranti P, Addeo F (2010) Hydroxyapatite affinity chromatography for the highly selective enrichment of mono- and multi-phosphorylated peptides in phosphoproteome analysis. Proteomics 10:380-393
52. Manning G, Whyte DB, Martinez R, Hunter T, Sudarsanam S (2002) The protein kinase complement of the human genome. Science 298:1912-1934 (Pubitemid 35425239)
53. Mazanek M, Mituloviae G, Herzog F, Stingl C, Hutchins JRA, Peters J-M, Mechtler K (2007) Titanium dioxide as a chemo-affinity solid phase in offline phosphopeptide chromatography prior to HPLC-MS/MS analysis. Nat Protoc 2:1059-1069 (Pubitemid 46901287)
54. McNulty DE, Annan RS (2008) Hydrophilic interaction chromatography reduces the complexity of the phosphoproteome and improves global phosphopeptide isolation and detection. Mol Cell Proteomics 7:971-980 (Pubitemid 351737096)
55. Miliotis T, Ericsson P-O, Marko-Varga G, Svensson R, Nilsson J, Laurell T, Bischoff R (2001) Analysis of regulatory phosphorylation sites in ZAP-70 by capillary high-performance liquid chromatography coupled to electrospray ionization or matrixassisted laser desorption ionization time-of-flight mass spectrometry. J Chromatogr B Biomed Sci Appl 752:323-334 (Pubitemid 32168166)
56. Molina H, Horn DM, Tang N, Mathivanan S, Pandey A (2007) Global proteomic profiling of phosphopeptides using electron transfer dissociation tandem mass spectrometry. Proc Nat Acad Sci 104:2199-2204 (Pubitemid 46391375)
57. Motoyama A, Xu T, Ruse CI, Wohlschlegel JA, Yates JR (2007) Anion and cation mixed-bed ion exchange for enhanced multidimensional separations of peptides and phosphopeptides. Anal Chem 79:3623-3634 (Pubitemid 46799057)
58. Muszynska G, Dobrowolska G, Medin A, Ekman P, Porath JO (1992) Model studies on iron(III) ion affinity chromatography: II. Interaction of immobilized iron(III) ions with phosphorylated amino acids, peptides and proteins. J Chromatogr A 604:19-28
59. Nabetani T, Kim Y-J, Watanabe M, Ohashi Y, Kamiguchi H, Hirabayashi Y (2009) Improved method of phosphopeptides enrichment using biphasic phosphate-binding tag/C18 tip for versatile analysis of phosphorylation dynamics. Proteomics 9:5525-5533
60. Neville DCA, Townsend RR, Rozanas CR, Verkman AS, Price EM, Gruis DB (1997) Evidence for phosphorylation of serine 753 in CFTR using a novel metal-ion affinity resin and matrix-assisted laser desorption mass spectrometry. Protein Sci 6:2436-2445 (Pubitemid 27490754)
61. Nie S, Dai J, Ning Z-B, Cao X-J, Sheng Q-H, Zeng R (2010) Comprehensive profiling of phosphopeptides based on anion exchange followed by flow-through enrichment with titanium dioxide (AFET). J Proteome Res 9:4585-4594
62. Olsen JV, Blagoev B, Gnad F, Macek B, Kumar C, Mortensen P, Mann M (2006) Global, in vivo, and site-specific phosphorylation dynamics in signaling networks. Cell 127:635-648 (Pubitemid 44647421)
63. Palumbo AM, Smith SA, Kalcic CL, Dantus M, Stemmer PM, Reid GE (2011) Tandem mass spectrometry strategies for phosphoproteome analysis. Mass Spectrom Rev 30(4):600-625
64. Pandey A, Podtelejnikov AV, Blagoev B, Bustelo XR, Mann M, Lodish HF (2000) Analysis of receptor signaling pathways by mass spectrometry: identification of Vav-2 as a substrate of the epidermal and platelet-derived growth factor receptors. Proc Nat Acad Sci USA 97:179-184 (Pubitemid 30055804)
65. Pinkse MWH, Uitto PM, Hilhorst MJ, Ooms B, Heck AJR (2004) Selective isolation at the femtomole level of phosphopeptides from proteolytic digests using 2D-NanoLC-ESI-MS/MS and titanium oxide precolumns. Anal Chem 76:3935-3943 (Pubitemid 38943662)
66. Porath J, Carlsson JAN, Olsson I, Belfrage G (1975) Metal chelate affinity chromatography, a new approach to protein fractionation. Nature 258:598-599
67. Posewitz MC, Tempst P (1999) Immobilized gallium(III) affinity chromatography of phosphopeptides. Anal Chem 71:2883-2892 (Pubitemid 29340481)
68. Reinders J, Sickmann A (2005) State-of-the-art in phosphoproteomics. Proteomics 5:4052-4061 (Pubitemid 41626073)
69. Rikova K, Guo A, Zeng Q, Possemato A, Yu J, Haack H, Nardone J, Lee K, Reeves C, Li Y et al (2007) Global survey of phosphotyrosine signaling identifies oncogenic kinases in lung cancer. Cell 131:1190-1203 (Pubitemid 350235027)
70. Rogers LD, Fang Y, Foster LJ (2010) An integrated global strategy for cell lysis, fractionation, enrichment and mass spectrometric analysis of phosphorylated peptides. Mol BioSyst 6:822-829
71. Rush J, Moritz A, Lee KA, Guo A, Goss VL, Spek EJ, Zhang H, Zha X-M, Polakiewicz RD, Comb MJ (2005) Immunoaffinity profiling of tyrosine phosphorylation in cancer cells. Nat Biotechnol 23:94-101 (Pubitemid 41724631)
72. Salomon AR, Ficarro SB, Brill LM, Brinker A, Phung QT, Ericson C, Sauer K, Brock A, Horn DM, Schultz PG et al (2003) Profiling of tyrosine phosphorylation pathways in human cells using mass spectrometry. Proc Nat Acad Sci USA 100:443-448 (Pubitemid 36126071)
73. Sano A, Nakamura H (2004) Chemo-affinity of titania for the columnswitchingHPLCanalysis of phosphopeptides.Anal Sci 20:565-566
74. Schroeder MJ, Shabanowitz J, Schwartz JC, Hunt DF, Coon JJ (2004) A neutral loss activation method for improved phosphopeptide sequence analysis by quadrupole ion trap mass spectrometry. Anal Chem 76:3590-3598 (Pubitemid 38868819)
75. Siepen JA, Keevil E-J, Knight D, Hubbard SJ (2007) Prediction of missed cleavage sites in tryptic peptides aids protein identification in proteomics. J Proteome Res 6:399-408 (Pubitemid 46173693)
76. Steen H, Küster B, Mann M (2001) Quadrupole time-of-flight versus triple-quadrupole mass spectrometry for the determination of phosphopeptides by precursor ion scanning. J Mass Spectrom 36:782-790 (Pubitemid 32737420)
77. Stensballe A, Jensen ON (2004) Phosphoric acid enhances the performance of Fe(III) affinity chromatography and matrixassisted laser desorption/ ionization tandem mass spectrometry for recovery, detection and sequencing of phosphopeptides. Rapid Commun Mass Spectrom 18:1721-1730 (Pubitemid 39024919)
78. Stensballe A, Andersen S, Jensen ON (2001) Characterization of phosphoproteins from electrophoretic gels by nanoscale Fe(III) affinity chromatography with off-line mass spectrometry analysis. Proteomics 1:207-222 (Pubitemid 33586717)
79. Thingholm TE, Larsen MR (2009) The use of titanium dioxide microcolumns to selectively isolate phosphopeptides from proteolytic digests. In: Walker JM (ed) Phospho-proteomics, Humana Press, USA, pp 57-66
80. Thingholm TE, Jensen ON, Robinson PJ, Larsen MR (2008a) SIMAC (sequential elution from IMAC), a phosphoproteomics strategy for the rapid separation of monophosphorylated from multiply phosphorylated peptides. Mol Cell Proteomics 7:661-671 (Pubitemid 351597478)
81. Thingholm TE, Larsen MR, Ingrell CR, Kassem M, Jensen ON (2008b) TiO2-based phosphoproteomic analysis of the plasma membrane and the effects of phosphatase inhibitor treatment. J Proteome Res 7:3304-3313
82. Thingholm TE, Jensen ON, Larsen MR (2009) Analytical strategies for phosphoproteomics. Proteomics 9:1451-1468
83. Thompson AJ, Hart SR, Franz C, Barnouin K, Ridley A, Cramer R (2003) Characterization of protein phosphorylation by mass spectrometry using immobilized metal ion affinity chromatography with on-resin b-elimination and Michael addition. Anal Chem 75:3232-3243 (Pubitemid 36830455)
84. Tsai C-F, Wang Y-T, Chen Y-R, Lai C-Y, Lin P-Y, Pan K-T, Chen J-Y, Khoo K-H, Chen Y-J (2008) Immobilized metal affinity chromatography revisited: pH/acid control toward high selectivity in phosphoproteomics. J Proteome Res 7:4058-4069
85. Ubersax JA, Ferrell JE Jr (2007) Mechanisms of specificity in protein phosphorylation. Nat Rev Mol Cell Biol 8:530-541 (Pubitemid 46985383)
86. Wa C, Cerny R, Hage DS (2006) Obtaining high sequence coverage in matrix-assisted laser desorption time-of-flight mass spectrometry for studies of protein modification: analysis of human serum albumin as a model. Anal Biochem 349:229-241 (Pubitemid 43184303)
87. Weckwerth W, Willmitzer L, Fiehn O (2000) Comparative quantification and identification of phosphoproteins using stable isotope labeling and liquid chromatography/mass spectrometry. Rapid Commun Mass Spectrom 14:1677-1681
88. Wisniewski JR, Zougman A, Nagaraj N, Mann M (2009) Universal sample preparation method for proteome analysis. Nat Methods 6:359-362
89. Wu J, Warren P, Shakey Q, Sousa E, Hill A, Ryan TE, He T (2010) Integrating titania enrichment, iTRAQ labeling, and Orbitrap CID-HCD for global identification and quantitative analysis of phosphopeptides. Proteomics 10:2224-2234
90. Xia Q, Cheng D, Duong DM, Gearing M, Lah JJ, Levey AI, Peng J (2008) Phosphoproteomic analysis of human brain by calcium phosphate precipitation and mass spectrometry. J Proteome Res 7:2845-2851
91. Ye J, Zhang X, Young C, Zhao X, Hao Q, Cheng L, Jensen ON (2010) Optimized IMAC-IMAC protocol for phosphopeptide recovery from complex biological samples. J Proteome Res 9:3561-3573
92. Zhang G, Neubert TA (2006) Use of detergents to increase selectivity of immunoprecipitation of tyrosine phosphorylated peptides prior to identification by MALDI quadrupole-TOF MS. Proteomics 6:571-578 (Pubitemid 43208036)
93. Zhang X, Ye J, Jensen ON, Roepstorff P (2007) Highly efficient phosphopeptide enrichment by calcium phosphate precipitation combined with subsequent IMAC enrichment. Mol Cell Proteomics 6:2032-2042 (Pubitemid 350201876)