Tandem Biocatalysis to Generate Hydrogen Sulfide and Promote Endogenous Antioxidant Response.

Promoting cellular protective responses during oxidative stress conditions through the generation of antioxidant persulfide (RS-SH) and hydrogen sulfide (HS) has tremendous therapeutic potential. Here, we report a bioinspired glycoconjugate, a candidate for tandem biocatalysis and generates persulfide/ HS in response to oxidative stress. The glycoconjugate is cleaved by β-galactosidase, an enzyme that is expressed during oxidative stress; the product of this reaction is a substrate for 3-mercaptopyruvate sulfurtransferase (3-MST), an enzyme that is involved in persulfide/ HS biosynthesis. The catalytic systems are orthogonal to one another, and the glycoconjugate is efficiently cleaved by these enzymes to generate the potent antioxidant glutathione persulfide as well as HS. We demonstrate the efficacy of this conjugate in mitigating inflammation in the brain in an animal model. Together, using rationally designed substrates and fully catalytic steps, we leverage tandem biocatalysis to direct the generation of persulfide/ HS, and promote cells' own antioxidant response.