ensüüm, mis katalüüsib tsüsteiinidel paiknevate vabade sulfüdrüülrühmade (SH) oksüdeerumist, selleks et moodustada disulfiidsildasid (S-S), An enzyme in the endoplasmic reticulum (ER) in eukaryotes and the periplasm of bacteria that catalyzes the formation and breakage of disulfide bonds between cysteine residues within proteins as they fold.