Thiotaurine is a sulfane sulfur donor to the biological thiols glutathione and cysteine.

Persulfide and hydrogen sulfide chemistry is relevant to the prevention of cellular oxidative damage. Thiotaurine is a poorly-studied precursor to the abundant biological molecule taurine and contains a labile sulfane sulfur. Here, reversible reactions of thiotaurine with glutathione or cysteine were investigated to observe formation of persulfides and hydrogen sulfide gas. Raman, Visible, and NMR spectroscopy were employed to characterize the reaction products and observe reaction kinetics. The reactions were verified through a kinetic competition experiment involving hydrogen peroxide. Data and kinetic models indicate initial transfer of the sulfane sulfur from thiotaurine to a free sulfide, followed by formation of disulfides and release of H2S gas. The findings identify thiotaurine as a candidate molecule involved in intracellular persulfide and H2S metabolism and suggest its cellular antioxidant behavior may be related to the transfer of its sulfane sulfur.