Tag Archives: nutrients
Activity of respiratory chain cytochrome complexes and cytochromes content in the rat kidney mitochondria under different nutrients content in a diet
H. P. Kopylchuk, O. M. Voloshchuk*
Educational and Scientific Institute of Biology, Chemistry and Natural Resources,
Yuriy Fedkovych Chernivtsi National University, Chernivtsi, Ukraine;
*e-mail: o.voloschuk@chnu.edu.ua
Received: 07 February 2023; Revised: 17 March 2023;
Accepted: 13 April 2023; Available on-line: 27 April 2023
An important role in ensuring the functioning of the respiratory chain belongs to the cytochrome part, which includes complexes III (ubiquinol-cytochrome c oxidoreductase) and IV (cytochrome c oxidase). The key components of these enzymatic complexes are heme-containing cytochromes, the number of which depends on the balance of heme synthesis and catabolism. δ-Aminolevulinate synthase catalyzes the first step of the heme biosynthetic pathway, while heme oxygenase is the key enzyme of heme degradation. It is known that nutritional imbalances drive many risk factors for chronic kidney disease. That is why our research aimed to study the activity of ubiquinol-cytochrome c oxidoreductase and cytochrome oxidase complexes, the level of cytochromes a+a3, b, c, and c1, and the activity of key enzymes of heme metabolism in the mitochondria of rat kidneys under conditions of different content of protein and sucrose in animal diet. The obtained results showed a decreased activity of ubiquinol-cytochrome c oxidoreductase and cytochrome oxidase complexes and reduced levels of mitochondria cytochromes a+a3, b, c, and c1 in the kidney mitochondria under the conditions of nutrient imbalance, with the most pronounced changes found in animals kept on a low-protein/high-sucrose diet. A decrease in δ-aminolevulinate synthase activity with a simultaneous 2-fold increase in heme oxygenase activity was found in kidney mitochondria of animals kept on a low-protein/high-sucrose diet compared to those kept on full-value diet indicating an intensification of heme catabolism along with inhibition of its synthesis. The obtained results testify the energy imbalance under the conditions of low-protein/high-sucrose which in turn can lead to the progression of kidney injury.
The NADH-ubiquinone reductase and succinate dehydrogenase activity in the rat kidney mitochondria under the conditions of different protein and sucrose content in the diet
O. M. Voloshchuk*, М. S. Ursatyy, G. P. Kopylchuk
Yuriy Fedkovych Chernivtsi National University, Institute of Biology, Chemistry and Natural Resources, Ukraine;
*e-mail: o.voloschuk@chnu.edu.ua
Received: 11 November 2021; Accepted: 21 January 2022
The NADH-ubiquinone reductase (EC 7.1.1.2) and succinate dehydrogenase (EC 1.3.5.1) activity, the levels of total ubiquinone and its redox forms, and the degree of oxidative modification of mitochondrial proteins in the rat kidney were investigated. It was found that when consuming a low-protein diet there is a decrease in NADH-ubiquinone reductase and succinate dehydrogenase activity by 1.4-1.7 times, a 20% decrease in total ubiquinone and a quantitative redistribution of its oxidized and reduced form with a predominance of oxidized form. Under the studied conditions, there is no accumulation of carbonyl derivatives, but the level of free SH-groups is significantly reduced compared with control. At the same time, in animals consuming a high-sucrose diet there is an increase in NADH-ubiquinone reductase and succinate dehydrogenase activity by 1.5-2 times and maintenance of the total ubiquinone at the control level against the background of redistribution of its redox forms, namely a decrease in reduced ubiquinone and an increase in oxidized ubiquinone on average by 1.5 times. In addition, there is an intensification of the reactions of free radical damage of mitochondrial proteins in kidney cells, as evidenced by an increase in the level of carbonyl derivatives and a significant decrease in the level of free protein SH-groups by approximately 1.4-1.5 times. The most pronounced changes in the studied indicators are found in animals that consumed a low-protein/high-sucrose diet. In particular, an excessive consumption of sucrose on the background of protein deficiency is accompanied by a reduction of NADH-ubiquinone reductase and succinate dehydrogenase activity by 1.7-2 times, a decrease in total ubiquinone level by approximately 1.4 times, and a two-fold decrease in reduced ubiquinone against the background of intensification of the free radical oxidation of mitochondrial proteins, which can be considered as a prerequisite for the impairment of the renal function under the conditions of carbohydrate-protein imbalance.