Figure 1. FIGURE 1: Scheme for the metabolic reduction of inorganic selenium forms, and their conversion into organic forms.

Reductive reactions are indicated with red arrows. Arrow 1 corresponds to the reactions involving ATP sulfurylase and other enzymes that take part in the initial steps of the sulfate assimilation pathway. Reactions 2 to 5 are non-enzymatic and result in the net conversion of reduced glutathione (GSH) into oxidized glutathione (GSSG). Reaction 6 is also non-enzymatic and results in the formation of diverse reactive oxygen species. Adapted from 25, 26, 27 and 36.