Document Detail

Electrochemistry and electrocatalysis with heme proteins in chitosan biopolymer films.
MedLine Citation:
PMID:  12234475     Owner:  NLM     Status:  MEDLINE    
Protein-chitosan (CS) films were made by casting a solution of proteins and CS on pyrolytic graphite electrodes. Myoglobin (Mb), hemoglobin (Hb), and horseradish peroxidase (HRP) incorporated in CS films gave a pair of stable, well-defined, and quasi-reversible cyclic voltammetric peaks at about -0.33V vs saturated calomel electrode in pH 7 buffers, respectively, while catalase (Ct) in CS films showed a peak pair at about -0.46V which was not stable. All these peaks are located at the potentials characteristic of heme Fe(III)/Fe(II) redox couples of the proteins. The electrochemical parameters such as formal potentials (E degrees (')) and apparent heterogeneous electron-transfer rate constants (k(s)) were estimated by square-wave voltammetry with nonlinear regression analysis. Chitosan films contained considerable water and formed hydrogel in aqueous solution. Positions of the Soret absorbance band suggest that Mb and Hb in CS films keep their secondary structure similar to the native states in the medium pH range, while HRP and Ct retain their native conformation at least in the dry CS films. Scanning electron microscopy of the films demonstrated that interaction between the proteins and CS would make the morphology of dry protein-CS films very different from the CS films alone. Oxygen, trichloroacetic acid, nitrite, and hydrogen peroxide were catalytically reduced by all four proteins in CS films.
He Huang; Naifei Hu; Yonghuai Zeng; Gu Zhou
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Analytical biochemistry     Volume:  308     ISSN:  0003-2697     ISO Abbreviation:  Anal. Biochem.     Publication Date:  2002 Sep 
Date Detail:
Created Date:  2002-09-17     Completed Date:  2003-03-20     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370535     Medline TA:  Anal Biochem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  141-51     Citation Subset:  IM    
Department of Chemistry, Beijing Normal University, China.
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MeSH Terms
Biopolymers / chemistry*
Catalase / metabolism
Chitin / analogs & derivatives*,  chemistry*
Hemoglobins / chemistry*
Horseradish Peroxidase / metabolism
Hydrogen Peroxide / chemistry
Liver / enzymology
Microscopy, Electron, Scanning
Myocardium / enzymology
Myoglobin / chemistry*
Nitrites / chemistry
Oxygen / chemistry
Sensitivity and Specificity
Spectrophotometry / methods
Trichloroacetic Acid / chemistry
Reg. No./Substance:
0/Biopolymers; 0/Hemoglobins; 0/Myoglobin; 0/Nitrites; 1398-61-4/Chitin; 76-03-9/Trichloroacetic Acid; 7722-84-1/Hydrogen Peroxide; 7782-44-7/Oxygen; 9012-76-4/Chitosan; EC 1.11.1.-/Horseradish Peroxidase; EC

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