3-mercaptopyruvate sulfurtransferase (MPST)

Also has weak rhodanese activity. Detoxifies cyanide and is needed for thiosulfate biosynthesis.

Acts as an antioxidant. In combination with cysteine aminotransferase (CAT), contributes to the catabolism of both cysteine and is an important producer of hydrogen sulfide in the brain, retina and vascular endothelial cells.