The Oxidation of Hypotaurine to Taurine: Bis-Aminoethyl-α-Disulfone, A Metabolic Intermediate in Mammalian Tissue

Open Questions Concerning Taurine with Emphasis on the Brain

“…We obtained some results, however, which indicated that the conversion was enzymatic (Oja and Kontro 1981 ). It has also been suggested that oxidation of hypotaurine to taurine might occur via a nonenzymatic S. S. Oja (*) • P. Saransaari Tampere University Medical School , Tampere , Finland e-mail: simo.oja@uta.fi reaction (Fellman et al 1987 ). This proposition has since been generally accepted without a convincing background of evidence.…”

The Interaction of Hypotaurine and Other Sulfinates with Reactive Oxygen and Nitrogen Species: A Survey of Reaction Mechanisms

“…It may initiate an oxygen-dependent radical chain propagation with a possible amplification of the oxidative mechanism ( in scheme 7) (Sevilla et al 1990;Flyunt et al 2001) or it can dimerize to form disulfone derivative (RSO 2 -SO 2 R), that subsequently hydrolyzes to yield RSO 3 -( in Scheme 7) (Ricci et al 1978;Fellman et al 1987;Green and Fellman 1994). The dimerization route does not require oxygen and can be operative in systems when low oxygen uptake is observed or in anaerobiosis (Ricci et al 1978;Pecci et al 1999;Baseggio Conrado et al 2015).…”

“…• is not the only one, actually, RSO 2 • can dimerize and produce the disulfone derivative (RSO 2 -SO 2 R) (Fellman et al 1987;Ricci et al 1978;Green and Fellman 1994). Pulse radiolysis studies carried out by our group, used to evaluate the oneelectron oxidation rate between RSO 2 -, HTAU and CSA, with • OH, CO 3 •-, and…”

“…This pathway is dependent upon three specific enzymes as well as a variety of biologically relevant oxidizing agents (scheme 1) (Huxtable 1992;Stipanuk and Ueki 2011;Ricci et al 1978;Fontana et al 2005;Fellman et al, 1987;Aruoma et al, 1988;Pecci et 1999;Baseggio Conrado et al 2014). It is well known that cysteine dioxygenase is the first enzyme involved in this pathway and its activity leads to CSA.…”

“…This crucial point, the sulfinic group oxidation to the respective sulfonic group, has never been associated with any specific enzyme (Wright et al 1986;Huxtable 1992). Conversely, evidences that in vivo formation of TAU and CA is the result of sulfinate (RSO 2 -) interaction with a variety of biologically relevant oxidizing agents, are strong (Ricci et al 1978;Fellman et al 1987;Aruoma et al 1988;Pecci et al 1999;Fontana et al 2005;Baseggio Conrado et al 2014). Scheme 1.…”