Disulfide Bond Formation in Prokaryotes and Eukaryotes

Publisher Summary This chapter reviews disulfide bond formation in prokaryotes and eukaryote. The formation of a disulfide bond in vivo is a controlled and catalyzed process. The catalysis of disulfide bond formation occurs via a thiol–disulfide exchange reaction between a disulfide donor and a target protein. Disulfide bond formation and isomerization are catalyzed processes in both prokaryotes and eukaryotes, and are achieved via thiol–disulfide exchange reactions with specific disulfide donors and isomerases. A mechanism for DsbB's oxidation of reduced DsbA has been proposed, and it involves a thiol–disulfide exchange cascade between DsbA and the two presumed disulfides of DsbB. Like DsbA, DsbC has a very reactive CXXC, which is only slightly less oxidizing than the CXXC of DsbA. Most of the proteins that are secreted from a eukaryotic cell contain disulfide bonds. In prokaryotes there is a clear separation between the oxidative and isomerase pathways. In eukaryotes a large number of PDI homologs with both PDI and oxidase activities cooperate to catalyze proper disulfide bond formation. Finally, this chapter concludes with a summary note on disulfide bond formation.