Alkylation of human serum albumin by sulfur mustard in vitro and in vivo: mass spectrometric analysis of a cysteine adduct as a sensitive biomarker of exposure.
To develop a mass spectrometric assay for the detection of sulfur mustard adducts with human serum albumin, the following steps were performed: quantitation of the binding of the agent to the protein by using [(14)C]sulfur mustard and analysis of acidic and tryptic digests of albumin from blood after exposure to sulfur mustard for identification of alkylation sites in the protein. The T5 fragment containing an alkylated cysteine could be detected in the tryptic digest with micro-LC/tandem MS analysis. Attempts to decrease the detection limit for in vitro exposure of human blood by analysis of the alkylated T5 fragment were not successful. After Pronase treatment of albumin, S-[2-[(hydroxyethyl)thio]ethyl]Cys-Pro-Phe was analyzed by means of micro-LC/tandem MS, allowing a detection limit for in vitro exposure of human blood of 10 nM, which is 1 order of magnitude lower than that obtained by means of modified Edman degradation. The analytical procedure could be successfully applied to the analysis of albumin samples from Iranian victims of the Iran-Iraq war.
Noort
D
D
Department of Chemical Toxicology, TNO Prins Maurits Laboratory, P.O. Box 45, 2280 AA Rijswijk, The Netherlands. noortd@pml.tno.nl
Hulst
A G
AG
de Jong
L P
LP
Benschop
H P
HP
D000477:Alkylating Agents / Q000097:blood / Q000737:chemistry*; D000478:Alkylation; D000595:Amino Acid Sequence; D015415:Biomarkers; D002618:Chemical Warfare; D002619:Chemical Warfare Agents / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000097:blood / Q000737:chemistry*; D006801:Humans; D006868:Hydrolysis; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009151:Mustard Gas / Q000737:chemistry*; D011485:Protein Binding; D012709:Serum Albumin / Q000737:chemistry*; D014357:Trypsin
D000477:Alkylating Agents; D015415:Biomarkers; D002619:Chemical Warfare Agents; D012709:Serum Albumin; D014357:Trypsin; D003545:Cysteine; D009151:Mustard Gas