Document Detail


Redox potential-pH properties of the flavoprotein L-amino-acid oxidase.
MedLine Citation:
PMID:  6712956     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The redox potential-pH characteristics of the enzyme L-amino-acid oxidase (L-amino-acid: oxygen oxidoreductase (deaminating), EC 1.4.3.2) have been measured in the pH range 6.2 to 8.3 at 4 degrees C. All potentials are reported versus the standard hydrogen electrode. Consistent with the protonation states proposed for the anionic red semiquinone and anionic dihydroquinone forms of the flavin coenzyme, the first electron potential is independent of pH (-0.056 +/- 0.006 V), while the second electron transfer potential is pH-dependent, exhibiting a 0.060 V/pH unit slope. At all pH values investigated, the percentage of semiquinone species observed matches closely that calculated from measured potential separations. The semiquinone species is thermodynamically stable, as indicated by formation of semiquinone, similarity of redox potentials in oxidative and reductive directions, and by the slope of Nernst plots.
Authors:
M T Stankovich; B G Fox
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Biochimica et biophysica acta     Volume:  786     ISSN:  0006-3002     ISO Abbreviation:  Biochim. Biophys. Acta     Publication Date:  1984 Apr 
Date Detail:
Created Date:  1984-06-18     Completed Date:  1984-06-18     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0217513     Medline TA:  Biochim Biophys Acta     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  49-56     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Amino Acid Oxidoreductases*
Animals
Chemistry, Physical
Crotalid Venoms / analysis*
Flavoproteins*
Hydrogen-Ion Concentration
L-Amino Acid Oxidase
Oxidation-Reduction
Physicochemical Phenomena
Potentiometry
Grant Support
ID/Acronym/Agency:
GM 29344/GM/NIGMS NIH HHS
Chemical
Reg. No./Substance:
0/Crotalid Venoms; 0/Flavoproteins; EC 1.4.-/Amino Acid Oxidoreductases; EC 1.4.3.2/L-Amino Acid Oxidase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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