Xh. Chen et al., Characterization for didodecyldimethylammonium bromide liquid crystal filmentrapping catalase with enhanced direct electron transfer rate, BIOSENS BIO, 16(1-2), 2001, pp. 115-120
Direct electrochemistry for catalase (CAT) embedded in the liquid crystal f
ilm of didodecyldimethylammonium bromide (DDAB) was investigated at pyrolyt
ic graphite (PG) electrode by voltammetric methods. The reduction reaction
involved the redox couple in CAT, i.e. Fe-III/Fe-II couple. The electron tr
ansfer between the incorporated CAT and PG electrode was found to be greatl
y enhanced by DDAB. The heterogeneous electron transfer rate constant k(s)
was fitted as 3.0 +/- 0.4 s(-1) using the nonlinear regression analysis of
the square wave voltammograms at a series of pulse heights. The pH dependen
ce of the formal potential for CAT in DDAB film was 57 mV/pH, which suggest
ed one-proton-transfer together with a one-electron reaction. Visible absor
ption and reflectance-absorbance infrared (RAIR) spectra inferred the simil
ar heme environment of CAT in DDAB film to its native status. Circular dich
roism (CD) results indicated DDAB affected slightly on the second structure
of CAT. (C) 2001 Elsevier Science B.V. All rights reserved.