Binding and Electron Transfer Reactions between Methanol Dehydrogenase and Its Physiologic Electron Acceptor Cytochrome c-551i: A Kinetic and Thermodynamic Analysis

Thomas K. Harris, Victor L. Davidson

Research output: Contribution to journalArticle

39 Scopus citations

Abstract

The quinoprotein methanol dehydrogenase and cytochrome c-551i form a physiologic complex in which electrons are transferred from pyrroloquinoline quinone to heme. The reoxidation of methanol dehydrogenase by the cytochrome was studied by stopped-flow spectroscopy. The rate constant for the electron transfer reaction and the dissociation constant for complex formation were each determined at temperatures ranging from 20 to 50°C. The electron transfer rates varied from 1.4 to 4.6 s-1. Analysis of the electron transfer reaction by Marcus theory yielded values of 1.9 eV for the reorganizational energy and 0.071 cm-1 for the electronic coupling and predicted a theoretical distance between redox centers of 15 Å. Kinetically determined dissociation constants correlated well with a Kd of 375 μM which was determined in a direct ultrafiltration binding assay. Thermodynamic analysis of the dissociation constants indicated the importance of the hydrophobic effect in complex formation.

Original languageEnglish (US)
Pages (from-to)14145-14150
Number of pages6
JournalBiochemistry
Volume32
Issue number51
DOIs
StatePublished - Jan 1 1993
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry

Fingerprint Dive into the research topics of 'Binding and Electron Transfer Reactions between Methanol Dehydrogenase and Its Physiologic Electron Acceptor Cytochrome c-551i: A Kinetic and Thermodynamic Analysis'. Together they form a unique fingerprint.

  • Cite this