Magnetic isotope and magnetic field effects on the rate of DNA synthesis catalysed by polymerases β with isotopic ions 24Mg2+, 25Mg2+ and 26Mg2+ in the catalytic sites were detected. No difference in enzymatic activity was found between polymerases β carrying 24Mg2+ and 26Mg2+ ions with spinless, non-magnetic nuclei 24Mg and 26Mg. However, 25Mg2+ ions with magnetic nucleus 25Mg were shown to suppress enzymatic activity by two to three times with respect to the enzymatic activity of polymerases β with 24Mg2+ and 26Mg2+ ions. Such an isotopic dependence directly indicates that in the DNA synthesis magnetic mass-independent isotope effect functions. Similar effect is exhibited by polymerases β with Zn2+ ions carrying magnetic 67Zn and non-magnetic 64Zn nuclei, respectively. A new, ion–radical mechanism of the DNA synthesis is suggested to explain these effects. Magnetic field dependence of the magnesium-catalysed DNA synthesis is in a perfect agreement with the proposed ion–radical mechanism. It is pointed out that the magnetic isotope and magnetic field effects may be used for medicinal purposes (trans-cranial magnetic treatment of cognitive deceases, cell proliferation, control of the cancer cells, etc).

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Materials and Methods Cell cultureThe HL-60 human myeloid leukemia cell line has been purchased from the Hungarian Cell Bank, Pasteur Institute of Hungary, Szeged, NCBI Code C427. Cells were maintained in suspension culture at +37°C under 5% CO 2 /air in RPMI 1640 (Gibco, UK) supplemented with 10% FCS and antibiotics: 100 U/mL Penicillin and 100 µg/mL Streptomycin. The cells were subcultured three times weekly, ATRA (Sigma, USA). This procedure has been originally adopted by Olins et al. [25] and then modified by Roy et al. [26]. Chromatin fractionationThe cells were precipitated by centrifugation at 12,000 rpm for 20 min (+4°C). The pellets were then suspended and homogenized in 5 volumes of 10 mM Tris-HCl (pH 7.80)/200 mM sucrose/1.5 mM EDTA/20 mM MgCl 2 /0.5% (v/v) Triton X100 using the glass-teflon Potter-Elvehjem homogenizer with a snug-fitting pestle (1,800 rpm).Homogenates were filtered through the 5-layer cotton graze and

Zinc is one of the most important microelements necessary for normal body functioning. Zinc is marked in numerous diseases and, hence, its properties and behavior in the body have long been a subject of extensive study. This review considers trends in the assessment of the role of zinc and its compounds in the past decade. It becomes evident that redox-inactive zinc is the main supervisor in the conformation of the most important molecules in all body organs and tissues. We placed emphasis on the variety of zinc-binding sites and the role of zinc in the genesis and progress of different forms of leukemia. The importance of some families of transcription factors in the development and prognosis of treatment of various leukemia forms is examined; new directions of these studies are shown.

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