TABLE 3.

Detection of selected chlorite dismutase (CD) and perchlorate reductase subunit A (PcrA) and subunit B (PcrB) peptide biomarkers under different growth conditions in the Bior enrichment culture

Growth condition	Chlorite dismutase		Perchlorate reductase subunit A		Perchlorate reductase subunit B
	Peptide sequence(s)	Mean concn (ng of CD/mg of total protein)a	Peptide sequence(s)	Mean concn (ng of Pcr A/mg of total protein)a	Peptide sequences	Mean concn (ng of Pcr B/mg of total protein)a
Phase of growth cycle
Early log phase	GLETNSDFFFR, GTILTQPGVFGVFTMFK, HKDNVLVDLYLTR, YVIVIPVKK	285	DIAPMPNIPEYNPR, EQTDLSYLVR, MDSTALYSDVVLPSAHWYEK, YIILWGSNPTQTR	1,051	GKIPPMIDYGIPFEFDYAGR, IEQGVAPACVAQCVGR, IPLAQLEGLFGK, IPPMIDYGIPFEFDYAGR, NVETAPGLGYPR, SAPNWDEDQGAGEYPNNSFFYLPR, VALPLHPEFGTEPNVFYVPPVLGPR	268
Mid-log phase	Same as above	271	Same as above	646	Same as above	225
Late log phase	Same as above	342	YIILWGSNPTQTR	317	Same as above	243
Perchlorate at indicated concn
0.1 mM	GTILTQPGVFGVFTMFK	641	YIILWGSNPTQTR	1,203	GKIPPMIDYGIPFEFDYAGR, IPLAQLEGLFGK, IPPMIDYGIPFEFDYAGR, VALPLHPEFGTEPNVFYVPPVLGPR	816
0.5 mM	GLETNSDFFFR, GTILTQPGVFGVFTMFK, YVIVIPVKK	1,237	DIAPMPNIPEYNPR, EQTDLSYLVR, YIILWGSNPTQTR	1,459	GKIPPMIDYGIPFEFDYAGR, IPLAQLEGLFGK, IPPMIDYGIPFEFDYAGR, SAPNWDEDQGAGEYPNNSFFYLPR, VALPLHPEFGTEPNVFYVPPVLGPR	774
1 mM	GLETNSDFFFR, GTILTQPGVFGVFTMFK, HKDNVLVDLYLTR, YVIVIPVKK	1,353	DIAPMPNIPEYNPR, EQTDLSYLVR, MDSTALYSDVVLPSAHWYEK, YIILWGSNPTQTR	1,645	GKIPPMIDYGIPFEFDYAGR, IEQGVAPACVAQCVGR, IPLAQLEGLFGK, IPPMIDYGIPFEFDYAGR, NVETAPGLGYPR, SAPNWDEDQGAGEYPNNSFFYLPR, VALPLHPEFGTEPNVFYVPPVLGPR	683
Perchlorate and nitrate at indicated concn
1.25 mM and 3.75 mM	GLETNSDFFFR, GTILTQPGVFGVFTMFK, HKDNVLVDLYLTR, YVIVIPVKK	410	DIAPMPNIPEYNPR, EQTDLSYLVR, MDSTALYSDVVLPSAHWYEK, YIILWGSNPTQTR	1,213	IEQGVAPACVAQCVGR,b NVETAPGLGYPR	655
1.67 mM and 3.3 mM	Same as above	725	Same as above	1,431	Same as above	622
2.5 mM and 2.5 mM	Same as above	160	Same as above	613	Same as above	227
Control
5 mM nitrate	None of the above		EQTDLSYLVR	10	None of the above

^aResults are the average of three mass spectrometric runs per sample. All the readings have a standard error of less than 12% of the mean.

^bThe rest of the peptide sequences (IPPMIDYGIPFEFDYAGR, IPLAQLEGLFGK; and SAPNWDEDQGAGEYPNNSFFYLPR, VALPLHPEFGTEPNVFYVPPVLGPR) match with peptides from respiratory nitrate reductase beta subunit from Dechloromonas aromatica strain RCB (UniProtKB protein database accession no. Q47CW7).