Reducing sugars can induce the oxidative inactivation of rhodanese

P. M. Horowitz, M. Butler, G. D. McClure

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The enzyme rhodanese (thiosulfate sulfurtransferase, EC 2.8.1.1) is inactivated on incubation with reducing sugars such as glucose, mannose, or fructose, but is stable with non-reducing sugars or related polyhydroxy compounds. The enzyme is inactivated with (ES) or without (E) the transferable sulfur atom, although E is considerably more sensitive, and inactivation is accentuated by cyanide. Inactivation of E is accompanied by increased proteolytic susceptibility, a decreased sulfhydryl titer, a red- shift and quenching of the protein fluorescence, and the appearance of hydrophobic surfaces. Superoxide dismutase and/or catalase protect rhodanese. Inactive enzyme can be partially reactivated during assay and almost completely reactivated by incubation with thiosulfate, lauryl maltoside, and 2-mercaptoethanol. These results are similar to those observed when rhodanese is inactivated by hydrogen peroxide. These observations, as well as the cyanide-dependent, oxidative inactivation by phenylglyoxal, are explained by invoking the formation of reactive oxygen species such as superoxide or hydrogen peroxide from autooxidation of α-hydroxy carbonyl compounds, which can be facilitated by cyanide.

Original languageEnglish (US)
Pages (from-to)23596-23600
Number of pages5
JournalJournal of Biological Chemistry
Volume267
Issue number33
StatePublished - 1992
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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