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Title: Nickel-specific, slow-binding inhibition of carbon monoxide dehydrogenase from Rhodospirillum rubrum by cyanide

Abstract

The inhibition of purified carbon monoxide dehydrogenase from Rhodospirillum rubrum by cyanide was investigated in both the presence and absence of CO and electron acceptor. The inhibition was a time-dependent process exhibiting pseudo-first-order kinetics under both sets of conditions. The true second-order rate constants for inhibition were 72.2 M{sup {minus}1} s{sup {minus}1} with both substrates present and 48.9 and 79.5 M{sup {minus}1} s{sup {minus}1}, respectively, for the reduced and oxidized enzymes incubated with cyanide. CO partially protected the enzyme against inhibition after 25-min incubation with 100 {mu}M KCN. Dissociation constants of 8.46 {mu}M (KCN) and 4.70 {mu}M (CO) were calculated for the binding of cyanide and CO to the enzyme. Cyanide inhibition was fully reversible under an atmosphere of CO after removal of unbound cyanide. N{sub 2} was unable to reverse the inhibition. The competence of nickel-deficient (apo) CO dehydrogenase to undergo activation by NiCl{sub 2} was unaffected by prior incubation with cyanide. Cyanide inhibition of holo-CO dehydrogenase was not reversed by addition of NiCl{sub 2}. {sup 14}CN{sup {minus}} remained associated with holoenzyme but not with apoenzyme through gel filtration chromatography. These findings suggest that cyanide is a slow-binding, active-site-directed, nickel-specific, reversible inhibitor of CO dehydrogenase. The authors propose thatmore » cyanide inhibits CO dehydrogenase by being a analogue of CO and by binding through enzyme-bound nickel.« less

Authors:
; ;  [1]
  1. Univ. of Wisconsin, Madison (USA)
Publication Date:
OSTI Identifier:
5300847
DOE Contract Number:  
FG02-87ER13691
Resource Type:
Journal Article
Journal Name:
Biochemistry; (USA)
Additional Journal Information:
Journal Volume: 28:12; Journal ID: ISSN 0006-2960
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; CYANIDES; BIOLOGICAL EFFECTS; ENZYME INHIBITORS; BIOCHEMICAL REACTION KINETICS; OXIDOREDUCTASES; INHIBITION; CARBON 14 COMPOUNDS; CARBON MONOXIDE; NICKEL CHLORIDES; RHODOSPIRILLUM; TRACER TECHNIQUES; BACTERIA; CARBON COMPOUNDS; CARBON OXIDES; CHALCOGENIDES; CHLORIDES; CHLORINE COMPOUNDS; ENZYMES; HALIDES; HALOGEN COMPOUNDS; ISOTOPE APPLICATIONS; KINETICS; LABELLED COMPOUNDS; MICROORGANISMS; NICKEL COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; REACTION KINETICS; TRANSITION ELEMENT COMPOUNDS; 550201* - Biochemistry- Tracer Techniques

Citation Formats

Ensign, S A, Hyman, M R, and Ludden, P W. Nickel-specific, slow-binding inhibition of carbon monoxide dehydrogenase from Rhodospirillum rubrum by cyanide. United States: N. p., 1989. Web. doi:10.1021/bi00438a011.
Ensign, S A, Hyman, M R, & Ludden, P W. Nickel-specific, slow-binding inhibition of carbon monoxide dehydrogenase from Rhodospirillum rubrum by cyanide. United States. https://doi.org/10.1021/bi00438a011
Ensign, S A, Hyman, M R, and Ludden, P W. 1989. "Nickel-specific, slow-binding inhibition of carbon monoxide dehydrogenase from Rhodospirillum rubrum by cyanide". United States. https://doi.org/10.1021/bi00438a011.
@article{osti_5300847,
title = {Nickel-specific, slow-binding inhibition of carbon monoxide dehydrogenase from Rhodospirillum rubrum by cyanide},
author = {Ensign, S A and Hyman, M R and Ludden, P W},
abstractNote = {The inhibition of purified carbon monoxide dehydrogenase from Rhodospirillum rubrum by cyanide was investigated in both the presence and absence of CO and electron acceptor. The inhibition was a time-dependent process exhibiting pseudo-first-order kinetics under both sets of conditions. The true second-order rate constants for inhibition were 72.2 M{sup {minus}1} s{sup {minus}1} with both substrates present and 48.9 and 79.5 M{sup {minus}1} s{sup {minus}1}, respectively, for the reduced and oxidized enzymes incubated with cyanide. CO partially protected the enzyme against inhibition after 25-min incubation with 100 {mu}M KCN. Dissociation constants of 8.46 {mu}M (KCN) and 4.70 {mu}M (CO) were calculated for the binding of cyanide and CO to the enzyme. Cyanide inhibition was fully reversible under an atmosphere of CO after removal of unbound cyanide. N{sub 2} was unable to reverse the inhibition. The competence of nickel-deficient (apo) CO dehydrogenase to undergo activation by NiCl{sub 2} was unaffected by prior incubation with cyanide. Cyanide inhibition of holo-CO dehydrogenase was not reversed by addition of NiCl{sub 2}. {sup 14}CN{sup {minus}} remained associated with holoenzyme but not with apoenzyme through gel filtration chromatography. These findings suggest that cyanide is a slow-binding, active-site-directed, nickel-specific, reversible inhibitor of CO dehydrogenase. The authors propose that cyanide inhibits CO dehydrogenase by being a analogue of CO and by binding through enzyme-bound nickel.},
doi = {10.1021/bi00438a011},
url = {https://www.osti.gov/biblio/5300847}, journal = {Biochemistry; (USA)},
issn = {0006-2960},
number = ,
volume = 28:12,
place = {United States},
year = {Tue Jun 13 00:00:00 EDT 1989},
month = {Tue Jun 13 00:00:00 EDT 1989}
}