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 Citations (Scopus)

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
Pages (from-to)14145-14150
Number of pages6
JournalBiochemistry
Volume32
Issue number51
StatePublished - Dec 1 1993
Externally publishedYes

Fingerprint

Cytochromes c
Thermodynamics
Electrons
Kinetics
PQQ Cofactor
Ultrafiltration
Cytochromes
Heme
Oxidation-Reduction
Rate constants
Assays
Spectrum Analysis
Spectroscopy
Temperature
alcohol dehydrogenase (acceptor)

ASJC Scopus subject areas

  • Biochemistry

Cite this

@article{db566a758d6b49989986260ef5f8c7f4,
title = "Binding and electron transfer reactions between methanol dehydrogenase and its physiologic electron acceptor cytochrome c-551i: A kinetic and thermodynamic analysis",
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 {\AA}. 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.",
author = "Harris, {Thomas K} and Davidson, {Victor L.}",
year = "1993",
month = "12",
day = "1",
language = "English",
volume = "32",
pages = "14145--14150",
journal = "Biochemistry",
issn = "0006-2960",
publisher = "American Chemical Society",
number = "51",

}

TY - JOUR

T1 - Binding and electron transfer reactions between methanol dehydrogenase and its physiologic electron acceptor cytochrome c-551i

T2 - A kinetic and thermodynamic analysis

AU - Harris, Thomas K

AU - Davidson, Victor L.

PY - 1993/12/1

Y1 - 1993/12/1

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=0027759655&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0027759655&partnerID=8YFLogxK

M3 - Article

C2 - 8260498

AN - SCOPUS:0027759655

VL - 32

SP - 14145

EP - 14150

JO - Biochemistry

JF - Biochemistry

SN - 0006-2960

IS - 51

ER -