Potentiometric CO titrations of carbon monoxide dehydrogenase and CO-inhibition of the NI-removing reaction with 1,10--phenanthroline /

(B.,, + e- = Bed) and a one-electron reduction and CO-

Bibliographic Details
Main Author: Russell, William Kent
Format: Thesis eBook
Language:English
Published: [Place of publication not identified] : [publisher not identified] ; 1996.
Subjects:
Online Access:Link to OAKTrust copy
Description
Summary:(B.,, + e- = Bed) and a one-electron reduction and CO-
2e- =C,,d2)(model 1) and a model that assumed two one-
acetyl-CoA) using three types of Ni and Fe-S structures
and CO2 atmospheres. The A, B, and C clusters EPR signals
atmosphere. The saturation properties of the B cluster EPR
atmosphere. The EPR signals of the A and C clusters also
binding of the A-cluster (A.,, + e- + CO = A[ ]-CO). The C-
called the A-, B-, and C-clusters. In this study, the enzyme
Carbon monoxide dehydrogenase from Clostridium thermoaceticum
catalyzes two reactions involving redox chemistry (the
chelating it. However, other studies suggest that CO binds
cluster was simulated using a two-electron reduction(Cedl +
CO implies that CO binds this Ni and blocks phen from
corresponding to the three clusters and the redox potential
developed at much lower concentrations of CO in a C02
developed at potentials -250, 150, and 250 mV more Positive,
e-= C[ ])(model 2). The development of EPR signals
electron reductions of the C-cluster(C[ ] + e- = Cint and Cit
of these clusters were found to be quite different under Ar
phen indirectly should be considered.
phenanthroline, with Ki = 840 atm-1. Since this reaction
reductant and substrate CO, under Ar and C02 atmospheres, and
respectively, under a C02 atmosphere relative to an Ar
reversible oxidation Of CO to C02, and the synthesis of
selectively removes the Ni from the A-cluster, inhibition by
signal (g,,, = 1.94)changed significantly under C02.
significance of the effect Of C02 is discussed. CO was found
simulated assuming a one-electron reduction of the B-cluster
spectroscopy (EPR). The resulting spectral changes were
that C02 binding effects a conformational change that alters
the enzyme's redox clusters. The possible catalytic
the reduction potentials and electron transfer properties of
then monitored by electron paramagnetic resonance
These C02 effects confirm and strengthen a previous proposal
to an Fe of the A-cluster, and the possibility that CO blocks
to inhibit the reaction of the enzyme with 1, I 0-
was incubated under various partial pressures of the
Item Description:"Major subject: Chemistry".
In title, symbols are used.
Vita.
Physical Description:ix, 45 leaves : illustrations ; 28 cm.
Also available online.
Issued also on microfiche from Lange Micrographics.
Bibliography:Includes bibliographical references: pages 42-44.