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Oxidation of 2-Mercaptobenzothiazole in latex gloves and its possible haptenation pathway.

Authors
Chipinda-I; Hettick-JM; Simoyi-RH; Siegel-PD
Source
Chem Res Toxicol 2007 Aug; 20(8):1084-1092
NIOSHTIC No.
20032359
Abstract
The rubber accelerator, 2-mercaptobenzothiazole (MBT), has been reported to cause allergic contact dermatitis from gloves and other rubber products, but its chemical fate when exposed to occupational oxidants and the mechanism of its pathogenesis are not known. It was hypothesized that the thiol group is critical to MBT's (its oxidation products or metabolites) covalent binding and/or haptenation to nucleophilic protein residues. Oxidative transformation of MBT to the disulfide 2,2'-dithiobis(benzothiazole) (MBTS) was observed within the glove matrix when hypochlorous acid, iodine, and hydrogen peroxide were used as oxidants. Cysteine reduced MBTS to MBT with subsequent formation of the mixed disulfide 2-amino-3-(benzothiazol-2-yl disulfanyl)propionic acid which was identified and characterized. Spectrophotometry and mass spectrometry experiments demonstrated the simultaneous reduction of MBTS and disulfide formation with Cys34 on bovine serum albumin, suggesting a potential route of protein haptenation through covalent bonding between protein cysteinyl residues and the MBT/MBTS thiol moiety. Metabolism of MBT using isoniazid and dexamethasone-induced rat liver microsomes, to give a protein reactive epoxide intermediate and provide an alternative protein haptenation mechanism, was not observed. The data suggest that the critical functional group on MBT is the thiol, and haptenation is via the formation of mixed disulfides between the thiol group on MBT and a protein sulfhydryl group.
Keywords
Allergies; Gloves; Personal-protective-equipment; Dermatitis; Oxidation; Thiols; Proteins; Mass-spectrometry; Mercaptans; Immune-system; Skin-exposure; Skin-irritants; Enzyme-activity; Epoxides
Contact
National Institute for Occupational Safety and Health, Health Effects Laboratory Division, Allergy and Clinical Immunology Branch, 1095 Willowdale Road, Morgantown, West Virginia 26505-2888
CODEN
CRTOEC
CAS No.
149-30-4; 120-78-5; 79-09-4
Publication Date
20070801
Document Type
Journal Article
Fiscal Year
2007
NTIS Accession No.
NTIS Price
Issue of Publication
8
ISSN
0893-228X
NIOSH Division
HELD
Source Name
Chemical Research in Toxicology
State
OR; WV
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