Tag Archives: furin activity
Influence of organic solvents on the furin activity
T. V. Osadchuk1, O. V. Shybyryn1, A. V. Semyroz1, V. K. Kibirev1,2
1Institute of Bioorganic Chemistry and Petrochemistry, National Academy of Sciences of Ukraine, Kyiv;
2Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: osadchuk@bpci.kiev.ua
Furin belongs to a family of calcium-dependent serine proprotein convertases, which transform the inactive protein precursors into mature polypeptides. In model experiments, we studied the effect of organic solvents such as acetone, dimethyl sulfoxide (DMSO), dioxane, isopropanol and ethanol on the furin activity. Furin was found to retain up to 88% of its initial activity in the presence of DMSO, whereas in the presence of acetone only 30%. Organic solvents formed the following decreasing sequence of their effects on furin: acetone> isopropanol> ethanol> dioxane> dimethyl sulfoxide. The relationship between the residual furin activity and solvent parameters such as relative polarity, dipole moment and log P were investigated. The effect of the organic solvent appeared not to correlate with any of the listed characteristics. Laidler-Sсatchard’s graphs, which according to a theory must be linear, demostrated non-linearity. These results indicate that not only electrostatic interactions play an important role in the studied enzymatic reaction but also other factors, e.g. hydrophobic contacts, hydrogen bonds can influence furin catalysis. This seems relevant for further research in this area.
Influence of cations on furin activity
T. V. Osadchuk1, O. V. Shybyryn1, A. V. Semyroz1,
O. M. Bondarenko1, V. K. Kibirev1,2
1Institute of Bioorganic Chemistry and Petrochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: osadchuk@bpci.kiev.ua;
2Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv
Furin is the most studied proprotein convertase which processes inactive protein precursors, converting them into biologically active polypeptides. We have investigated cation effects of cesium, strontium, cadmium, iron, cobalt and nickel on the furin activity. It was shown that in the presence of Ca2+ (1 mM) these ions were able to activate the enzyme, and the peak position of its activity depends on the nature of the ion. Particularly, for Fe2+ it was observed at the ion concentration of 15 mM, whereas for Cd2+, Co2+ and Ni2+ the maximum activity of furin was at 20 mM, for Cs+ the peak was at a concentration of 30 mM, and for strontium ions it was 40 mM. The affinity of the cations for furin was estimated by Lineweaver-Burk plots for low concentrations of ions for the ascending branch of furin activity dependence on the cation concentration. It was found that their affinity in comparison with Ca2+ was sharply reduced (~ 18-150 times). The studied cations (under physiological conditions) were shown not to be able to compete with calcium ions for furin, and in natural environment they cannot influence its activity.