Table 1.

P-Labeled Lysine-Containing Peptides Observed in Tryptic Digests

#	Species	Protein	Peptidea	Residueb number	gi: numberc	Peptided mass	OPe
1	Human	Serum Albumin	AFK*AWAVAR	K212	28592	1155.4	CPO
2	Human	Serum Albumin	K*VPQVSTPTLVEVSR	K414	28592	1775.5	CPO
3	Human	Serum Albumin	Y*TKK*VPQVSTPTLVEVSR	K414 Y411	28592	2307.4	CPO
4	Human	Serum Albumin	LK*CASLQK	K199	28592	1083.4	CPO
5	Human	Serum Albumin	LAK*TYETTLEK	K351	28592	1461.0	DFP
6	Human	Keratin 1	FLEQQNQVLQTK*WELLQQVDTSTR	K211	119395750	3069.1	CPO
7	Human	Keratin 1	SLDLDSIIAEVK*AQYEDIQK	K355	119395750	2486.5	CPO
8	Human	Keratin 10	LASYLDK*VR	K163	47744568	1200.7	CPO
9	Bovine	Tubulin alpha	DVNAAIATIK*TK	K336	73586894	1380.8	CPO
10	Bovine	Tubulin alpha	LSVDY*GK*K	K163 Y161	73586894	1181.6	CPO
11	Bovine	Tubulin alpha	LDHK*FDLMYAK	K394	73586894	1517.0	CPO
12	Bovine	Tubulin alpha	FDLMY*AK*R	K401 Y399	73586894	1315.6	CPO
13	Bovine	Tubulin alpha	Y*AK*R	K401 Y399	73586894	809.4	CPO
14	Bovine	Tubulin alpha	TIGGGDDSFNTFFSETGAGK*HVPR	K60	73586894	2633.4	CPO
15	Bovine	Tubulin beta	K*Y*VPR	K58 Y59	75773583	934.0	CPO
16	Bovine	Actin	VAPEEHPTLLTEAPLNPK*ANR	K113	62287933	2433.7	CPO
17	Bovine	Actin	DLTDYLMK*ILTER	K291	62287933	1746.4	CPO
18	Bovine	Actin	EITALAPSTMK*IK	K326	62287933	1538.4	CPO
19	Bovine	Actin	MQK*EITALAPSTMK	K315	62287933	1684.3	CPO
20	Bovine	Actin	IK*IIAPPER	K328	62287933	1172.5	CPO
21	Mouse	Transferrin	DLLFK*DSAFGLLR	K296	21363012	1631.4	CPO
22	Mouse	Transferrin	STTK*DLLFR	K626	21363012	1217.0	CPO

^aK* indicates the labeled lysine. Y* indicates a labeled tyrosine in the same peptide.

^bNumbering is for the mature sequence, except for the keratins which are numbered from the gene sequence.

^cThe gi number is the NCBI accession number for the protein from PubMed.

^dThese are the measured, singly-charged, average masses [M+H]¹⁺ for the labeled peptides. Peptides containing Cys are carbamidomethylated.

^eCPO= chlorpyrifos oxon; DFP=diisopropyl fluorophosphate