Differential Detergent Solubility Investigation of Thermally Induced Transitions in Cytochrome c Oxidase

Christopher W. Rigell, Ernesto Freire

Research output: Contribution to journalArticle

Abstract

The thermal denaturation of membrane-reconstituted cytochrome c oxidase (EC 1.9.3.1) occurs at ~63 °C as determined by high-sensitivity differential scanning calorimetry. The heat capacity profile associated with this process is characterized by the presence of two well-defined peaks, indicating that all the enzyme subunits do not have the same thermal stability. This thermal denaturation of the enzyme complex is coupled to a change in its solubility properties. This change in solubility allows separation of the native and denatured protein fractions by detergent solubilization followed by centrifugation under conditions in which only the native fraction is solubilized. Using this principle, it has been possible to study the denaturation of membrane-reconstituted cytochrome c oxidase and quantitatively identify the protein subunits undergoing thermal denaturation using computer-assisted gel electrophoresis analysis. This technique allows calculation of single-subunit thermal denaturation profiles within the intact enzyme complex, and as such, it can be used to obtain transition temperatures, molecular populations, and van’t Hoff enthalpy changes for individual protein subunits, thus complementing results obtained by high-sensitivity differential scanning calorimetry.

Original languageEnglish (US)
Pages (from-to)4366-4371
Number of pages6
JournalBiochemistry
Volume26
Issue number14
DOIs
StatePublished - Jan 1 1987

ASJC Scopus subject areas

  • Biochemistry

Fingerprint Dive into the research topics of 'Differential Detergent Solubility Investigation of Thermally Induced Transitions in Cytochrome c Oxidase'. Together they form a unique fingerprint.

  • Cite this