Tag Archives: hydrogen peroxide
The influence of iron ions on ATP-hydrolases activity of cell membranes of rat colon smooth muscle and kidney
A. A. Kaplia
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: kaplya@biochem.kiev.ua
To elucidate the specific features of the АТР- hydrolases structural resistance in the membrane under the action of the prooxidants: Fe2+ and hydrogen peroxide, and N-ethylmaleimide (NEM) the colonic smooth muscle (CSM) Na+,K+-AТРase activity was compared with activities of the corresponding Mg2+-АТР-hydrolase and ATP-ases from kidney medullar layer of rats. The inhibition study of the CSM Na+,K+-AТРase by divalent iron shows the decrease of the activity by 30% at 0.1 µM FeSO4 and in the range of 0.1-10 µM – to 45% of residual activity. When comparing with kidney enzyme (represents exclusively α1-isozyme) the CSM Na+,K+-AТРase sensitivity to Fe2+ is reliably higher at its submicromolar concentration. CSM Mg2+-АТРase is much more resistant to iron ions effect, than kidney one. However for two tissues Mg2+-АТРase activity is always more resistant as compared with corresponding Na+,K+-AТРase activity. Against 1 mM EGTA Na+,K+-AТРase and Mg2+-АТРase activities of GMOK and kidneys are equally insensitive to effect of hydrogen peroxide in concentration up to 1 mM. But in the presence of 20 µM FeSO4 in the concentration range of 1 nМ – 1 mM of Н2О2 the Na+,K+-AТРase is inhibited to greater extent, than Mg2+-АТРase activity. NEM sensitivity of the two АТР-hydrolase systems corresponds to prooxidant sensitivity that indicates the distinct importance of SH-groups for their functioning.
It is concluded that Na+,K+-AТРase can serve as a marker of membrane sensitivity to oxidation, Mg2+-АТРase is resistant to oxidation and can be considered as criterion of the oxidation resistance when comparing membrane enzyme complexes, especially in GMOK.
Analysis of creatine kinase activity with evaluation of protein expression under the effect of heat and hydrogen peroxide
A. D. Rakhmetov1, Lee Sang Pil2, L. I. Ostapchenko1, Chae Ho Zoon2
1Education and Science Center Institute of Biology Taras Shevchenko National University of Kyiv, Ukraine;
2Chonnam National University, Gwangju, South Korea;
e-mail: anar.rakhmetov@gmail.com
Protein oxidation has detrimental effects on the brain functioning, which involves inhibition of the crucial enzyme, brain type creatine kinase (CKBB), responsible for the CK/phosphocreatine shuttle system. Here we demonstrate a susceptibility of CKBB to several ordinary stressors. In our study enzymatic activity of purified recombinant brain-type creatine kinase was evaluated. We assayed 30 nM concentration of CKBB under normal and stress conditions. In the direction of phosphocreatine formation hydrogen peroxide and heat treatments altered CKBB activity down to 26 and 14%, respectively. Also, examination of immunoblotted membrane patterns by SDS-PAGE electrophoresis and western blot analysis showed a decrease in expression levels of intrinsic CKBB enzyme in HeLa and A549 cells. Hence, our results clearly show that cytosolic CKBB is extremely sensitive to oxidative stress and heat induced inactivation. Therefore, due to its susceptibility, this enzyme may be defined as a potential target in brain damage.