Disulfide bond generation in mammalian blood serum: detection and purification of quiescin-sulfhydryl oxidase.

ABSTRACT: A sensitive new plate-reader assay has been developed showing that adult mammalian blood serum contains circulating soluble sulfhydryl oxidase activity that can introduce disulfide bonds into reduced proteins with the reduction of oxygen to hydrogen peroxide. The activity was purified 5000-fold to >90% homogeneity from bovine serum and found by mass spectrometry to be consistent with the short isoform of quiescin-sulfhydryl oxidase 1 (QSOX1). This FAD-dependent enzyme is present at comparable activity levels in fetal and adult commercial bovine sera. Thus cell culture media that are routinely supplemented with either fetal or adult bovine sera will contain this facile catalyst of protein thiol oxidation. QSOX1 is present at approximately 25 nM in pooled normal adult human serum. Examinatio

SUBMITTER: Israel BA 

PROVIDER: S-EPMC3960832 | biostudies-literature | 2014 Apr

REPOSITORIES: biostudies-literature