Protein Modifications by Low Molecular Weight Chemicals Inducing Airways Diseases

Abstract: Airways diseases are one of the most common health effects in the western world today. It has been shown that low molecular weight chemicals (LMWC) can cause airways diseases. The mechanisms for these diseases are not well known in most cases. Also, methods for biological monitoring of exposure are not available for many of these LMWC. This limits the possibility for diagnostics and prevention. The binding of LMWC to endogenous proteins may be of relevance for the pathophysiological mechanism. Thus, modifications caused by organic acid anhydride (OAAs), persulfate and acrylates on hemoglobin (Hb) and human serum albumin (HSA) was studied in this thesis. The OAAs were found adducted to N-terminal valines and lysines. New methods using the computer softwares MSight and MoDetect were developed for identification of novel modifications by persulfate and acrylates on proteins. Persulfate oxidized tryptophans and methionines in both Hb and HSA, whereas the acrylates adducted cysteines in Hb. Liquid chromatography tandem mass spectrometry methods using selected reaction monitoring were developed for digested modified peptides, as a step toward developing methods for biological monitoring of exposure. It was shown that methylhexahydrophthalic anhydride (MHHPA) adducted peptides could be measured in nasal lavage collected from workers exposed to low levels of MHHPA and that oxidized peptides were found in digests of Hb from a subject in the reference population. It seems that the site of modification may be of importance for the effect but this has to be further evaluated.