Optimized verification method for detection of an albumin-sulfur mustard adduct at Cys34 using a hybrid quadrupole time-of-flight tandem mass spectrometer after direct plasma proteolysis

Methionine329 in human serum albumin: A novel target for alkylation by sulfur mustard

“…Therefore, toxicity of SM is assumed to be due to the alkylation of proteins and DNA resulting in the functional impairment of cells, tissues, organs, and physiological processes. 12,[17][18][19][20][21][22][23] Based on the proteolysis of alkylated HSA, several analytical methods targeting the Cys 34 modification as HETE-CysProPhe (HETE-CPF) and HETE-CysPro (HETE-CP) were developed and have proven to be reliable biomarkers of exposure in vitro, in vivo, and in real cases of SM poisoning. 2 For the verification of an alleged use of SM, protein adducts reveal beneficial long-term stability of several weeks or even months in vivo when compared to products of SM hydrolysis and enzymatic biotransformation.…”

“…Due to its bifunctional structure, crosslinks between biomolecules may occur. 12,[15][16][17][18][19][20][21][22][23][24] Herein, we present Met 329 as an additional target of SM in HSA. 15,16 Most relevant biomarkers are alkylated peptides derived from human serum albumin (HSA).…”

Modification of human serum albumin by the nerve agent VX: microbore liquid chromatography/electrospray ionization high‐resolution time‐of‐flight tandem mass spectrometry method for detection of phosphonylated tyrosine and novel cysteine containing disulfide adducts

“…It was shown that certain tyrosine residues are prone to phosphylation (denominating both phosphorylation and phosphonylation) by numerous OP and that Cys 34 – the only amino acid containing a free thiol group – can easily be modified by electrophiles (e.g. by alkylation with sulfur mustard) . Subsequent enzymatic cleavage of HSA allows generation of small cleavage products, which are analyzed using liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI‐MS/MS).…”

“…Especially, current lots of commercially available pronase, a mixture of several endo‐ and exopeptidases isolated from Streptomyces griseus , show favorable cleaving properties ultimately leading to single amino acids (e.g. tyrosine) and the cysteine‐proline dipeptide (CP)‐containing Cys 34 …”

Identification of novel disulfide adducts between the thiol containing leaving group of the nerve agent VX and cysteine containing tripeptides derived from human serum albumin

“…While phosphylation is the critical step of AChE inhibition by modification of its active site serine residue, we have recently shown that the corresponding leaving group of VX (2-(diisopropylamino)ethanethiol, DPAET) is also capable of forming adducts with endogenous cysteine residues of HSA [25] . Cys-Pro dipeptides including the only free cysteine sidechain at position 34 (C 34 P) were already known to result from pronase cleavage of HSA and facilitated the identification of DPAET-CP as a novel biomarker for VX exposure in vitro [8,[14][15][16][17]25] . Enzymatic cleavage of HSA incubated with VX using pronase resulted in cysteine and proline containing small peptides.…”