Table VIII.

Ratios of iTRAQ-labelled phosphopeptides derived from protein kinases and protein phosphatases in Xenopus eggs without and with a Ca²⁺-stimulus^a

	Xenopus protein								Human orthologue protein
No.	Accession	Name	Sequence and siteb	117/114 Ratio					Accession	Site
				1	2	3	Average	SD
1	gi117949815	MAPK 1	VADPDHDHTGFLtEYVATR, T188	0.252	0.252	0.279	0.261	0.017	gi66932916	T185
2	gi117949815	MAPK 1	VADPDHDHTGFLtEyVATR, T188, Y190	0.448	0.565	0.328	0.447	0.127	gi66932916	T185, Y187
3	gi82209768	ribosomal protein S6 Kinase 2 alpha	GFsFVAPALVEEDAK, S380	0.431	0.489	0.671	0.530	0.134	gi292457	S380
4	gi148228921	ribosomal protein S6 kinase, 90 kDa, polypeptide 3	DsPGIPAsANAHQLFR, S366, S372	0.531	0.589	0.662	0.594	0.070	gi1730070	S369, S375
5	gi147902292	TTK protein kinase	ILGQLIGLNsPNSISR, S844	0.789	0.701	0.613	0.701	0.094	gi23308722	S821
6	gi125694	ribosomal protein S6 Kinase 2 beta	GFsFVAPVLVEEDAK, S380	0.917	0.646	1.364	0.976	0.389	gi15929013	S380
7	gi148228921	ribosomal protein S6 kinase, 90 kDa, polypeptide 3	DsPGIPASANAHQLFR, S366	0.948	1.154	1.215	1.106	0.150	gi1730070	S369
8	gi148225112	casein kinase 1, epsilon	ISAsQAsVPFDHLGK, S405, S408	1.672	0.984	1.178	1.278	0.380	gi23199991	S405, S408

^aPhosphopeptides in tryptic digests of cytosol fractions (3 mg protein) of Xenopus eggs without and with a Ca²⁺-stimulus were purified with an automated phosphopeptide purification system with the 1-step method, and then modified with 114- and 117-iTRAQ, respectively. The labelled phosphopeptides were mixed, desalted and then dissolved in a EDTA-containing solvent. The labelled phosphopeptides derived from 1.6 mg protein were analysed three times by LC MS/MS, and then the 117/114 ratios were determined. The 117/114 ratios of phosphopeptides derived from protein kinases and protein phosphatases, and reproducibly quantified three times are listed.

^bLower-case letters indicate phosphorylated amino acid residues.