|
D. V. Smirnova, V. K. Koltover, S. V. Nosenko, I. A. Strizhova, N. N. Ugarova
Firefly
luciferase bioluminescence as a tool for searching magnetic isotopic effects in
ATP-dependent enzyme reactions
Abstract
Cells and tissues are composed from atoms of chemical elements, some of
which have two kinds of stable isotopes, magnetic and nonmagnetic ones. Not
long ago, magnetic isotope effects (MIEs) have been discovered in experiments
with the cells enriched with magnetic or nonmagnetic isotopes of magnesium.
These MIEs can stem from higher efficiency of the enzymes in the cells enriched
with magnetic magnesium isotope. In the studies of MIEs in biological systems,
it is needed to monitor the ATP concentrations as the major
energy currency in cells. The most sensitive and rapid method of the ATP assay is
based on the use of the firefly luciferase-luciferin system. Since luciferase
is the ATP-dependent enzyme and activated by Mg-ions, it is necessary to
elucidate whether this enzyme is sensitive to magnetic field of the magnesium
isotope’s nuclear spin. Herein we present the results of studying the effects
of different isotopes of magnesium, magnetic 25Mg and nonmagnetic 24Mg
and 26Mg, on bioluminescence spectra and enzymatic activity of
firefly luciferase. It was shown, that neither kinetics of the bioluminescence nor the bioluminescence spectra
have manifested any statistically significant dependence on the type of
magnesium isotope. So, no MIEs have been revealed in the luciferase-catalyzed
oxidation of luciferin. It means that firefly luciferase bioluminescence can
serve as the tool for search and studies of magnetic isotope effects in
ATP-dependent enzyme reactions in biological systems, including the enzymatic
synthesis and hydrolysis of ATP.
Key words: firefly luciferase, luciferin, ATP-Mg, magnetic isotope
effect, magnesium.
Copyright (C) Chemistry Dept., Moscow State University, 2002
|
|
