Table 2.

Identification of Na-K-ATPase phosphorylated peptides from ouabain-treated HKC-11 cells

Peptide m/z	Putative Modifications	Start Sequence	End Sequence	Missed Cleavages	Peptide Amino Acid Sequence
2,554.157	1Phospho	662	683	1	(K)ACVVHGSDLKDMTSEQLDDILK(Y)
	1Met-ox
2,093.914	3Phospho	608	625	1	(R)SAGIKVIMVTGDHPITAK (A)
1,139.453	2Phospho	256	264	0	(R)GIVVYTGDR(T)
1,453.528	2Phospho	10	21	0	(K)YEPAAVSEQGDK(K)
2,537.037	3Phospho	75	94	1	(R)DGPNALTPPPTTPEWIKFCR(Q)

Table shows peptide mass, phosphorylation site, and putative peptide sequences from the immunoprecipitated 100-kDa band. The peptide sequences that showed homology with the Na-K-ATPase α1-subunit are shown. Peptide 4 shows the known tyrosine phosphorylation of the Na-K-ATPase α1-subunit (Tyr-10). The other 4 peptides show putative unique serine/tyrosine phosphorylation sites in ouabain-treated samples. These peptides were not identified in control samples.