Studies of the reactivity of morpholine, 2-mercaptobenzothiazole and 2 of their derivatives with selected amino acids.

Previous studies in guinea pigs showed that DTDM, MMBT and MBT were sensitizing agents. The purpose of this study was to investigate the biochemical basis of this sensitization reaction. The reactions of representative amino acids, Cys, Lys & Gly, with morpholine, DTDM, MMBT & MBT were examined. New compounds were found between MMBT and all 3 amino acids. Additional new compounds were seen for Cys/MBT, Cys/DTDM, Lys/MBT & Gly/DTDM. No reaction was observed with morpholine. The new compounds were examined spectroscopically. Results suggest that the sensitizing nature of DTDM is probably a reaction of its disulfide bond with the -SH & -NH2 groups of amino acid moieties. The conjugation of Cys/MMBT may be via the same reaction mechanism. The -SH group of MBT may react either via oxidation and/or thioester formation with the carboxylate group of amino acids. These results also suggest that in vitro tests may predict the sensitizing potential of certain compounds.