Document Detail


Modulation of the reactivity of the thiol of human serum albumin and its sulfenic derivative by fatty acids.
MedLine Citation:
PMID:  22450170     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The single cysteine residue of human serum albumin (HSA-SH) is the most abundant plasma thiol. HSA transports fatty acids (FA), a cargo that increases under conditions of diabetes, exercise or adrenergic stimulation. The stearic acid-HSA (5/1) complex reacted sixfold faster than FA-free HSA at pH 7.4 with the disulfide 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) and twofold faster with hydrogen peroxide and peroxynitrite. The apparent pK(a) of HSA-SH decreased from 7.9±0.1 to 7.4±0.1. Exposure to H(2)O(2) (2mM, 5min, 37°C) yielded 0.29±0.04mol of sulfenic acid (HSA-SOH) per mole of FA-bound HSA. The reactivity of HSA-SOH with low molecular weight thiols increased ∼threefold in the presence of FA. The enhanced reactivity of the albumin thiol at neutral pH upon FA binding can be rationalized by considering that the corresponding conformational changes that increase thiol exposure both increase the availability of the thiolate due to a lower apparent pK(a) and also loosen steric constraints for reactions. Since situations that increase circulating FA are associated with oxidative stress, this increased reactivity of HSA-SH could assist in oxidant removal.
Authors:
María José Torres; Lucía Turell; Horacio Botti; Laura Antmann; Sebastián Carballal; Gerardo Ferrer-Sueta; Rafael Radi; Beatriz Alvarez
Publication Detail:
Type:  In Vitro; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2012-03-19
Journal Detail:
Title:  Archives of biochemistry and biophysics     Volume:  521     ISSN:  1096-0384     ISO Abbreviation:  Arch. Biochem. Biophys.     Publication Date:  2012 May 
Date Detail:
Created Date:  2012-05-04     Completed Date:  2012-06-22     Revised Date:  2013-08-06    
Medline Journal Info:
Nlm Unique ID:  0372430     Medline TA:  Arch Biochem Biophys     Country:  United States    
Other Details:
Languages:  eng     Pagination:  102-10     Citation Subset:  IM    
Copyright Information:
Copyright © 2012 Elsevier Inc. All rights reserved.
Affiliation:
Laboratorio de Enzimología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay.
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MeSH Terms
Descriptor/Qualifier:
Crystallography, X-Ray
Dithionitrobenzoic Acid / metabolism,  pharmacology
Fatty Acids / metabolism,  pharmacology*
Humans
Hydrogen Peroxide / metabolism,  pharmacology
Hydrogen-Ion Concentration
Models, Molecular
Oxidation-Reduction
Protein Binding
Protein Stability
Serum Albumin / chemistry*,  drug effects,  metabolism
Sulfenic Acids / chemistry,  metabolism
Sulfhydryl Compounds / chemistry,  metabolism
Sulfhydryl Reagents / metabolism,  pharmacology
Grant Support
ID/Acronym/Agency:
1R01AI095173-01/AI/NIAID NIH HHS; R01 AI095173/AI/NIAID NIH HHS; R01 AI095173-01/AI/NIAID NIH HHS; //Howard Hughes Medical Institute
Chemical
Reg. No./Substance:
0/Fatty Acids; 0/Serum Albumin; 0/Sulfenic Acids; 0/Sulfhydryl Compounds; 0/Sulfhydryl Reagents; 69-78-3/Dithionitrobenzoic Acid; 7722-84-1/Hydrogen Peroxide
Comments/Corrections

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