Acceptor substrate-potentiated inactivation of bovine liver rhodanese

B. A. Aird, P. M. Horowitz

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

The interaction of bovine liver rhodanese (thiosulfate:cyanide sulfurtransferase, EC 2.8.1.1) with the acceptor substrates, dithiothreitol or cyanide, was studied. When incubated in the presence of cyanide or dithiothreitol, rhodanese was inactivated in a time-dependent process. This inactivation was detectable only at low enzyme concentrations; the rate and degree of inactivation could be modulated by varying the substrate concentration or the system pH. Activity measurements and fluorescence spectroscopy techniques were used in examining the inactivation phenomenon. Sulfur transfer to dithiothreitol was measured by direct assay and was shown to involve the dequenching of enzymic intrinsic fluorescence that had been previously observed only with cyanide as the acceptor substrate. Substrate-potentiated inactivation of rhodanese (with cyanide) has been reported before, but the cause and nature of this interaction were unexplained. The results presented here are consistent with an explanation invoking oxidation of rhodanese in the course or inactivation.

Original languageEnglish (US)
Pages (from-to)15270-15276
Number of pages7
JournalJournal of Biological Chemistry
Volume263
Issue number30
StatePublished - 1988
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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