Biochemistry and Molecular Biology
Cystamine is commonly used as a transglutaminase inhibitor. This disulfide undergoes reduction in vivo to the aminothiol compound, cysteamine. Thus, the mechanism by which cystamine inhibits transglutaminase activity in vivo could be due to either cystamine or cysteamine, which depends on the local redox environment. Cystamine inactivates transglutaminases by promoting the oxidation of two vicinal cysteine residues on the enzyme to an allosteric disulfide, whereas cysteamine acts as a competitive inhibitor for transamidation reaction catalyzed by this enzyme. The latter mechanism is likely to result in the formation of a unique biomarker, N -(gamma-glutamyl)cysteamine that could serve to indicate how cyst(e)amine acts to inhibit transglutaminases inside cells and the body.
Jeitner, T. M., Pinto, J., & Cooper, A. (2018). Cystamine and Cysteamine As Inhibitors of Transglutaminases In Vivo. Bioscience Reports, 38 (5), BSR20180691. https://doi.org/10.1042/BSR20180691
Originally published in Bioscience Reports, 38(5), BSR20180691. The original material can be found here.
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