Sulfites glutathione metabolism

Reed GA, Ryan MJ, Adams KS. Sulfite enhancement of diolepoxide mutagenicity The role of altered glutathione metabolism. Carcinogenesis 1990 11 (9) 1635-9. 

Because grape must contain little organic sulfur, in the form of S-amino acids and glutathione, yeast assimilates sulfate, and sulfite when added, for the synthesis of organic sulfur compounds. Sulfur metabolism is important in winemaking since, depending on the yeast strain and nutrient composition, it is the source of mostly unpleasant compounds, including H2S and mercaptans (Rauhut 1993). 

Fig. 6.3 Generalized overview of Se metabolism in plants. Numbers denote known enzymes. (1) ATP sulfurylase, (2) adenosine-5-phosphosulfate reductase, (3) glutathione or sulfite reductase, (4) glutathione reductase or O-acetylserine thiol lyase, (5) Selenocysteine methyltransferase, (6) Selenocysteine lyase, (7) cystathionine-g-synthase, (8) cystathionine-b-lyase, (9) methionine synthase, (10) methionine methyltransferase, (11) DMSP lyase, (12) g-gjutamylcysteine synthetase (Source Parker et al. (2003), Sors et al. (2005b), Pilon-Smits and Quinn (2010), Lindblom et al. (2012), Yu and Gu (2013), PUon-Smits et al. (2014), Winkel et al. (2015) and PUon-Smits (2015))...

---