Electrochemistry and electrocatalytic properties of heme proteins incorporated in lipopolysaccharide films

摘要

The electrochemical behavior of heme proteins such as hemoglobin (Hb), myoglobin (Mb), and horseradish peroxidase (HRP) was studied in stable thin films composed of the proteins and a natural bacterial endotoxin (lipopolysaccharide, LPS). All three protein-LPS films exhibited a pair of well-defined, quasi-reversible cyclic voltammetric peaks in pH 6.0 phosphate buffers. Moreover, hydrogen peroxide and trichloroacetic acid could be reduced catalytically by the proteins entrapped in the films. Electrochemical parameters. such as the apparent Michaelis-Menten constant (K-m(app)) and formal potentials (E-0), were obtained. The positions of the Soret absorption band of the proteins suggested that the three proteins could keep their secondary structure in LPS films.