Ondrej Zitka,a,b Ales Horna,c Karel Stejskal,a,b Josef Zehnalek,a Vojtech Adam,a Ladislav Havel,d Ladislav Zeman,e Rene Kizeka,*
a
Department of Chemistry and Biochemistry, d Department of Plant Biology, and
e Department of Animal Nutrition, Mendel University of Agriculture
and Forestry,Zemedelska 1, CZ-613 00
Brno, Czech Republic.
Tel. +420(5)45133350,
Fax: +420(5)45212044,
E-mail: kizek@sci.muni.cz.
b
Department of Biochemistry, Faculty of Science, Masaryk University,Kotlarska 2, CZ-611 37
Brno, Czech Republic
c
Department of Food Engineering and Chemistry, Faculty of Technology,Tomas Bata University,
CZ-762 72 Zlin, Czech Republic
Paper based on a
presentation at the 12th International Symposium on Separation
Sciences, Lipica, Slovenia,
September 27–29, 2006.
Abstract
Lactoferrin is
considered to be a multifunctional protein. It appears to play several
biologically important roles, where
its structure
is very crucial. The aim of this work was to investigate the basic
electrochemical behaviour of lactoferrin by both stationary and flow
electrochemical methods with respect its structural changes under various
denaturing conditions. The electroactivity of lactoferrin was studied by three
various electrochemical methods (linear sweep, differential pulse and square
wave voltammetry). Based on the results obtained, we utilized flow injection
analysis with electrochemical detection (FIA-ED) for determination of
lactoferrin. We found out that the most suitable FIA-ED conditions were as
follows: working electrode potential of 900 mV, Britton-Robinson buffer (pH 4.5)
as the mobile phase, its flow rate 1 ml min–1. Finally, we attempted
to follow the changes of lactoferrin signal in the presence of chemical
compounds or under the physical conditions leading to changes in its structure.
As we have shown here, electrochemical analysis enables us to distinguish
changes of protein structure easily and rapidly.
Keywords: lactoferrin, milk protein, linear sweep voltammetry, differential pulse voltammetry, square wave voltammetry, carbon paste electrode, glassy carbon electrode