Peroxidase activity of erythrocytes hemoglobin under action of low-frequency vibration

Background. Hemoglobin is a hemoprotein which in the presence of oxidative equivalents, such as H2O2, can act as peroxidase with a very high oxidative potential. Hemoglobin oxidation is accompanied by generation of highly oxidized forms of iron and globin radicals that have high oxidative activity and are toxic to cells. In addition, peroxidase activity may indicate structural changes that occur in the hemoglobin molecule as a result of chemical modification. Materials and Methods. Erythrocyte suspension was subjected to vibration for 3 h within the frequency range from 8 to 32 Hz with amplitudes of 0.5 ± 0.04 and 0.9 ± 0.08 mm. At certain intervals, hemoglobin peroxidase activity was determined together with the content of its ligand forms in the hemolysates of cells. Additionally, experiments were performed to investigate the mechanism and calculate the kinetic parameters of peroxidase reaction. Results and Discussion. Experimental data on low-frequency vibrations effect on erythrocyte hemoglobin peroxidase activity were analyzed. The kinetics of the oxidation reaction of p-phenylenediamine by hemoglobin in erythrocytes was studied. It was found that peroxidase oxidation has a ping-pong mechanism. The kinetic parameters of the peroxidase reaction involving hemoglobin were determined. The change of kinetic parameters after two-hour exposure to the incubation medium and low-frequency vibration was studied. A possible mechanism of action of hemoglobin in oxidation reactions involving H2O2 was proposed. Conclusion. Any effect that initiates the formation of methemoglobin leads to an increase in the peroxidase activity of hemoglobin due to the involvement of the latter in the pseudoperoxidase cycle and the formation of toxic reactive globin radicals. The high content of oxyhemoglobin in the cell, observed under vibrations within the frequency range of 16–32 Hz with an amplitude of 0.9 ± 0.08 mm, can prevent its oxidation and involvement in the pseudoperoxidase cycle.

Vеterinary and sanitary assessment of meat of foals of the Oymyakonsky region of Sakha (Yakutia) Republic at helminthoses

This article presents data on the spread of horse helminth infestations in the Oymyakonsky region, postmortem examination of carcasses and organs of foals, as well as organoleptic, physical and chemical, microbiological studies of meat of foals slightly and strongly infested with helminths in a comparative aspect. According to the results of organoleptic studies of meat from weakly invaded foals meet the requirements of GOST -7269-79, GOST 32225-2013 and can be consumed as food without restrictions. Meat from heavily invaded animals differs from weakly invaded animals in organoleptic indicators. The meat has a red crust of dried carcass, folded, slightly moist, the muscles on the cut are moist, but don't leave a damp spot on the filter paper, expressed red color. The consistency of the muscle is tight, elastic, the dimple formed by pressing with the finger is slowly smoothed out. The smell of the meat is peculiar to that of foals. The fat is soft, slightly sticky and yellowish. The broth is cloudy, with flakes. Physico-chemical investigations showed that meat samples from weakly invaded foals meet the requirements of normative documents GOST R-51478-99, GOST-23392-78. During the comparative evaluation of the meat of weakly invaded and heavily invaded, the following indicators were established: peroxidase reaction - "positive", aminoammonia nitrogen content - 0.84, pH - 5.8. When adding copper sulfate solution to the broth under study, insignificant flakes appeared, while maintaining broth transparency - the reaction is "doubtful". In heavily invaded foals, meat quality does not meet GOST: peroxidase reaction is "negative", reaction with copper sulfate is dubious, meat broth is turbid, with flakes; aminoammoniacal nitrogen content is 1.4, pH - 6.2. The results of microbiological investigations of the meat of weakly invaded foals meet the requirements of normative documents GOST-32031-2012, GOST-10444.15-94. Detected in the meat of heavily invaded foals BSCP (coliforms), KMAFANM (coliforms) - 8*103, indicating that the meat obtained from heavily invaded foals on microbiological indicators, the established standards do not correspond. Consequently, the indicators of meat of weakly invaded foals correspond to fresh, good-quality meat, and the meat of heavily invaded foals is recommended for use in food after industrial processing.

Inhibition of Lipoxygenase and Peroxidase Reaction by Some Flavonols and Flavones: The Structure-Activity Relationship

Some flavonoids were investigated for their effects on lipoxygenase and peroxidase. The strongest inhibitor of lipoxygenase was kaempferol with one hydroxyl group situated at the 4’ position in the B ring, with activity of 21.2±2.03 calculated per μmole of compound. The weakest inhibition was observed for diosmetin with a hydroxyl group at the 3′ position and a methoxyl group at 4′ in the B ring, with activity of 1.17±0.77 per μmole. Peroxidase was most strongly inhibited by quercetin (22.7±0.05) with two hydroxyl groups in the B ring at 3′ and 4′. The weakest inhibitor of peroxidase was genkwanin (0±0.16) with one hydroxyl group at position 4′ in the B ring and methoxyl at position 7 in the A ring. The correlation coefficient between reduction of Fe3+ by flavonoids and inhibition of lipoxygenase by these compounds was 0.72 and the reduction of Fe3+ and inhibition of peroxidase was 0.24. The results show that inhibition of peroxidase is weakly associated with reducing properties of phenols and inhibition of lipoxygenase may be associated with antioxidant properties of flavonoids.