ИСТИНА

Myoglobin (Mb) participates in human respiration both as an oxygen store and as an entity facilitating oxygen diffusion, thereby supporting cellular respiration in cardiac and skeletal muscle tissues. In addition to conventional functions, it can possibly act, as has been recently proposed, as an intracellular scavenger of nitric oxide (NO) to protect mitochondrial cytochrome c oxidase from its inhibition by NO.[1] In healthy organism, in the absence of inflammation or injury of muscle tissues myoglonin does not release into the circulation. Myoglobin detection is very important for express diagnosis of AMI, crush syndrome, hypoxia neonatorum, overtraining of sportsman, as well as in forensic medicine as an additional criterion for fatal poisoning with ethanol and drugs of opiate group. Myoglobin belongs to the family of heme proteins, whose active center (heme) contains a coordinated Fe(III) ion. Our research group was the first to make use of the electrochemical properties of myoglobin for its detection in biological body fluids.[2-4] The proposed method is based on internal electroactivity of myoglobin and direct detection of its interaction with specific antibodies. Thus, myoglobin can be quantitatively detected by direct electron transfer reaction from an electrode surface to ion Fe(III): Mb–Fe(III) + e– + H+ → Mb–Fe(II); Mb–Fe(II) + O2  [Mb–Fe(II)O2 ]  Mb–Fe(III) + O2 – In this scheme, oxygen participates in the catalytic reaction. However, this electrocatalytic reaction may be realized only by using special modifiers of the electrode surface, its nanostructuring. Nanostructuring provides direct electron transfer between electrode and the myoglobin heme, thus enabling to register the signal and to reach a very low limit of detection. Golden, silver, copper nanoparticles and carbon black were used for electrode surface modification. It was shown that carbon black dispersion improves the sensitivity of myoglobin detection. Cathodic peak of cardiac Mb reduction was proportional to Mb concentration in human plasma. The required sample volume is 0.25–1 µl depending on the electrode surface, while the analytical procedure takes no more than 30 min. The developed electrochemical method can be used for express diagnostics of acute myocardial infarction, other diseases and disease states, as well as, for investigation of myoglobin functions in physiological processes. This work was financially supported by the Federal Agency of Science and Innovations, Russian Federation Ministry of Education and Science (Contract № 16.512.11.2215). 1. K. Shikama, Progress in Biophysics and Molecular Biology 2006, 91, 83; 2. V. Shumyantseva, E. Suprun, T. Bulko, A. Archakov, Electroanalysis 2009, 21, 530; 3. E. Suprun, T. Bulko, A. Lisitsa, O. Gnedenko, A. Ivanov, V. Shumyantseva, A. Archakov, Biosens. Bioelectron. 2010, 25, 1694; 4. E. V. Suprun, A. L. Shilovskaya, A. V. Lisitsa, T. V. Bulko, V. V. Shumyantseva, A. I. Archakov, Electroanalysis 2011, 23, 1051;