Tag Archives: cytochrome c
ABTS oxidation reaction as a model of cytochrome c-driven electron transfer
F. Gudratova, A. Aliyeva, S. Mahmudova, K. Gasimov, T. Yusifov*
Institute of Biophysics, Ministry of Science and Education
of the Republic of Azerbaijan, Baku;
*e-mail: tjussifo@ucla.edu
Received: 23 May 2025; Revised: 24 July 2025;
Accepted: 12 September 2025; Available on-line: 17 September2025
Cytochrome c, as an electron carrier within the mitochondria, plays a crucial role in the electron transport chain. To meet the demand for rapid methods that assess the electron transport properties of cytochrome c, we used the electron donor 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonate) (ABTS) as a substrate and suitable spectrophotometric reporter of cytochrome c peroxidase-like activity. ABTS and cytochrome c from bovine were purchased from Sigma-Aldrich Inc. The time course of the cytochrome c-driven ABTS oxidation reaction was studied using H2O2 as a second substrate. It was demonstrated that CytC addition is a prerequisite for the transfer of electrons from ABTS to H2O2. The reaction kinetic analysis with determination of Vmax, Km, kcat, and kcat/Km values for both substrates was performed. Our results demonstrate that the cytochrome c-catalyzed ABTS oxidation reaction can be effectively employed as a model for studying the functional role of cytochrome c in various conditions.
Choline derivatives as natural ligands of mitochondrial nicotinic acetylcholine receptors
O. Lykhmus, M. Izmailov, M. Skok*
Department of Molecular Immunology, Palladin Institute of Biochemistry,
National Academy of Sciences of Ukraine, Kyiv;
*e-mail: skok@biochem.kiev.ua
Received: 16 March 2023; Revised: 28 April 2023;
Accepted: 05 June 2023; Available on-line: 20 June 2023
Nicotinic acetylcholine receptors (nAChRs) regulate mitochondria-driven apoptosis; however, their intracellular ligands are unknown. In the present paper, we show that choline and its derivatives (phosphocholine (PC), L-α-glycerophosphocholine (G-PC) and 1-palmitoyl-sn-glycero-3-phosphocholine (P-GPC)) dose-dependently influence cytochrome c release from isolated mouse liver mitochondria. Choline inhibited Ca2+-stimulated cytochrome c release, while PC attenuated wortmannin-induced cytochrome c release. Small doses of G-PC and P-GPC (up to 0.1 µM) were protective against either Ca2+ or wortmannin, while larger doses (up to 1 µM) stimulated cytochrome c release by themselves. Choline and PC disrupted interaction of VDAC1, Bax and Bcl-2 with mitochondrial α7 nAChRs and favored their interaction with α9 nAChR subunits. It is concluded that choline metabolites can regulate apoptosis by affecting mitochondrial nAChRs.
Free radical oxidation in liver mitochondria of tumor-bearing rats and its correction by essential lipophilic nutrients
O. V. Ketsa, M. M. Marchenko
Fedkovich Chernivtsy National University, Ukraine;
e-mail: o.ketsa@chnu.edu.ua
Received: 21 May 2019; Accepted: 29 November 2019
The role of free radical oxidation in the increase of mitochondrial membranes permeability in organs which are not involved in oncogenesis and the development of the methods for preventing mitochondria dysfunction remain topical problems. In this work, the interconnection of lipid peroxidation (LPO) in liver mitochondrial fraction with the processes of mitochondrial swelling and cytochrome с release to the cytosol under separate and combined administration of ω-3 polyunsaturated fatty acids (PUFAs) and retinol acetate (vitamin A acetate) to rats with transplanted Guerin’s carcinoma was studied. During the intensive tumor growth (14 days) the increase of superoxide radical generation and the content of primary (triene conjugates, TC), secondary (ketodienes and coupled trienes, CD+CT) and terminal (Schiff bases) lipid peroxidation products in the mitochondrial fraction of tumor-bearing rats was detected, which contributed to the mitochondrial swelling and cytochrome с release to the cytosol. Separate administration of ω-3 PUFAs to tumor-bearing rats decreased both free radical processes in mitochondrial fraction and mitochondrial swelling. Separate administration of retinol acetate in a high dose (3000 IU/kg of body weight) intensified free radical processes in the mitochondrial fraction of tumor-bearing rats, while administration of retinol acetate in a physiological dose (30 IU/kg of body weight) did not lead to changes compared to tumor-bearing rats that did not receive the drug. The prooxidant effects of retinoid were partially eliminated in the case of combined administration with ω-3 PUFA.
Photoactivated fullerene C(60) induces store-operated Ca(2+) entry and cytochrome c release in Jurkat cells
S. M. Grebinyk1, K. O. Palyvoda2, S. V. Prylutska1, I. I. Grynyuk1,
A. A. Samoylenko2, L. B. Drobot2, O. P. Matyshevska1
1Taras Shevchenko Kyiv National University, Ukraine;
2Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: matysh@yahoo.com
The values of endoplasmic reticulum Ca2+-pool and store-operated Ca2+ entry (SOCE) were estimated in rat thymocytes and Jurkat cells loaded with indo-1 and treated with thapsigargin. It was shown that the relative value of SOCE in thymocytes was substantially lower than in Jurkat cells. Significant increase of SOCE in Jurkat cells preincubated with 10-5 M C60 and exposed to uv/visible light irradiation was detected at 1-3 h after exposure. At this time FCCP-induced Ca2+-release from mitochondria was shown to be reduced, while cytochrome c level into the cytoplasm of Jurkat cells, detected by Western blot analysis, to be increased. It is supposed that Ca2+ flux remodulation induced by photoexcited fullerene C60 in Jurkat cells might be involved in the initiation of signalling events leading to cell apoptosis.