Isoquinoline Coumarin Derivatives as Chemiluminescence Activators in Reactions of Lipid Peroxidation

Abstract

This study deals with participation of isoquinoline derivatives of coumarin in the peroxidase reaction catalyzed by the cytochrome c–cardiolipin complex. We have studied coumarin derivatives called coumarin-314 (C-314), coumarin-334 (C-334) and coumarin-525 (C-525). These substances are considered as specific physical activators of chemiluminescence, which accompanies the lipid peroxidation reaction. In the course of the scientific research, a spectrophotometric study of the effect of methanol on the structure of cytochrome c was performed, the optical properties of these substances were studied in the medium of a phosphate buffer, and a spectrophotometric study was performed with parallel registration of the chemiluminescence of a mixture in which cytochrome c catalyzed by a complex with cardiolipin lipoperoxidase reaction in the presence of isoquinolysin derivatives of coumarin. The conclusions of this work contain identification of the reversibility of the action of methanol on the structure of cytochrome c, which proves the possibility of using this alcohol in the study of this protein, the positions of absorption maxima and corresponding values of molar absorption coefficients in the medium of 20 mM phosphate buffer (pH = 7.4) for C-314 (λmax = 447.5 nm; e = 32360.4 L/(mol cm)), C-334 (λmax = 460 nm; e = 44 012 L/(mol cm)), and C-525 (λmax = 460 nm; e = 32 703.56 L/(mol cm)). We also demonstrated that the said substances are substrates of cytochrome c/cardiolipin complex-catalyzed peroxidase reaction. Mass flow of these substances during an average statistical experiment in measurement of chemiluminescence (322 s) for C-314, C-334 and C-525 amounted to 31.89, 37.61 and 25.94%, respectively.