EPR STUDIES OF THE EFFECT OF CONCENTRATION
OF COPPER(II) AND ZINC(II) IONS ON PAMAGNETIC PROPERTIES
OF THE MIXED TYPE MELANIN BIOPOLIMER
Magdalena Zdybel1, Barbara Pilawa1, Ewa Buszman2, Teresa Witoszyńska2
1, 2
Medical University of Silesia in Katowice, School of Pharmacy and Laboratory Medicine,
1
Department of Biophysics, Jedności 8, 41-200 Sosnowiec,
2
Department of Pharmaceutical Chemistry, Jagiellońska 4, 41-200 Sosnowiec
EPR studies of the complexes of the natural melanin existed in pigmented soil fungi
Cladosporium cladosporioides with paramagnetic copper(II) and diamagnetic zinc(II) ions
were performed. The aim of this work was to determine effect of concentration of the metal
ions on paramagnetic centers in the studied melanin. The results were compared with our
earlier data for the others concentrations of the metal ions in melanin-Cu(II) and melaninZn(II) complexes.
Cladosporium cladosporioides are soil fungi, which contain melanin biopolymers. The
culture of the tested fungi is presented in Figure 1. The fungi were complexed with Cu(II) and
Zn(II). The concentrations of the metal ions of 1 x 10-3 and 1 x 10-4 were used.
Fig. 1. The culture of Cladosporium cladosporioides.
The measurements were done by the use of an X-band (9.3 GHz) EPR spectrometer
produced by RADIOPAN Firm (Poznań) and the EPRAD Firm (Poznań) system of data
acquisition. Modulation of magnetic field of 100 kHz was used. Frequency of microwave
radiation was measured by MCM recorder of EPRAD Firm (Poznań). Lineshape and
parameters of the EPR spectra in the range of microwave power of 0.7-70 mW were analysed.
Concentration of paramagnetic centers in the examined melanin samples was determined.
The complex shape of the EPR spectra was observed. The experimental EPR spectra
were superposition of eu- and pheomelanin lines. The exemplary EPR spectrum of
Cladosporium cladosporioides sample is shown in Figure 2.
6 0 0 0
4 0 0 0
1 1mT
melanina z Cl.cl.
2 0 0 0
0
3 3 2
- 2 0 0 0
- 4 0 0 0
- 6 0 0 0
3 3 3
3 3 4
3 3 5
3 3 6
3 3 7
3 3 8
3 3 9
3 4 0
Fig. 2. EPR spectrum of melanin in Cladosporium cladosporioides. This spectrum was
measured with microwave power of 0.7 mW.
It was obtained that concentrations of paramagnetic centers in the studied melanin
depend on type and concentration of metal ions. Paramagnetic copper(II) ions decreases
paramagnetic centers concentration and diamagnetic zinc(II) ions increases its value. These
effects are stronger for the higher metal ions concentrations. Microwave saturation of the
spectra were observed. The results were correlated with data obtained for melanin complexes
with iron(III) [1] and cadmium(II) ions [2].
Acknowledgements
This study was supported by Medical University of Silesia in Katowice (KNW-1-096/10 and
KNW-1-126/10).
References
[1] Chodurek E, Zdybel M, Pilawa B. Abstracts of the XIII Conference of Polish Biophysics
Society. Curr Top Biophys (page B-26).
[2] Matuszczyk M, Buszman B, Pilawa B, Witoszyńska T, Wilczok T. Chem Phys Lett 2004;
394: 366-371.