Enzymatic and non-enzymatic conversion of cystamine to thiotaurine and taurine.

Autor: Karpowicz SJ; Department of Physical Sciences, Eastern New Mexico University, Portales, NM, USA. Electronic address: steven.karpowicz@enmu.edu., Anderson L; Department of Physical Sciences, Eastern New Mexico University, Portales, NM, USA.
Jazyk: angličtina
Zdroj: Biochimica et biophysica acta. General subjects [Biochim Biophys Acta Gen Subj] 2022 Dec; Vol. 1866 (12), pp. 130225. Date of Electronic Publication: 2022 Aug 18.
DOI: 10.1016/j.bbagen.2022.130225
Abstrakt: The disulfide-containing molecule cystamine and the thiosulfonate thiotaurine are of interest as therapeutics. Both are precursors of taurine, but the chemistry of their metabolism is not clear. The rates at which these molecules are metabolized is also unknown. The chemistry and rate constants have been determined for a process in which cystamine is converted in four reactions to thiotaurine. Cystamine is oxidized by diamine oxidase with a specificity constant comparable to other diamine substrates. The rapid hydrogen peroxide-mediated oxidation of cystaldimine yields reactive glyoxal and thiocysteamine, which quickly performs transsulfuration with hypotaurine. Thiotaurine reacts spontaneously with hydrogen peroxide to form taurine and sulfite, but it is 15-fold less reactive than hypotaurine as an antioxidant. An estimation of biological rates of reaction indicates that cystamine is likely to be oxidized by diamine oxidase in vivo, but its metabolic products will be diverted to molecules other than thiotaurine.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2022 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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