Peroxide stimulated transition between the ferryl intermediates of bovine cytochrome c oxidase.

During catalysis of cytochrome c oxidases (CcO) several ferryl intermediates of the catalytic heme a-Cu center are observed. In the P ferryl state, produced by the reaction of two-electron reduced CcO with O, the ferryl iron of heme a and a free radical are present at the catalytic center. The radical reduction stimulates the transition of the P into another ferryl F state.

Thermodynamics of the P-type Ferryl Form of Bovine Cytochrome c Oxidase.

Several ferryl states of the catalytic heme a-Cu center of the respiratory cytochrome c oxidases (CcOs) are observed during the reduction of O2 to H2O. One of the P-type ferryl forms, P, is produced by the reaction of the two-electron reduced CcO with O2. In this state, the heme a iron is in the ferryl state and a free radical should be also present at the catalytic center.

Modulation of the electron-proton coupling at cytochrome a by the ligation of the oxidized catalytic center in bovine cytochrome c oxidase.

Cytochrome a was suggested as the key redox center in the proton pumping process of bovine cytochrome c oxidase (CcO). Recent studies showed that both the structure of heme a and its immediate vicinity are sensitive to the ligation and the redox state of the distant catalytic center composed of iron of cytochrome a (Fe) and copper (Cu). Here, the influence of the ligation at the oxidized Fe-Cu center on the electron-proton coupling at heme a was examined in the wide pH range (6.

Synthesis, structural characterization and biological activity of novel Knoevenagel condensates on DLD-1 human colon carcinoma.

Biologically active Knoevenagel condensates (1-14) of diarylheptanoids: 1,7-bis(3-methoxy-4-hydroxyphenyl)hepta-1,7-diene-3,5-dione and 1,7-bis(3-ethoxy-4-hydroxyphenyl)hepta-1,7-diene-3,5-dione, were synthesized and structurally characterized. Compounds 1-14 exhibited cytotoxicity against colon carcinoma cells, and their antiproliferative effect was associated with a significant decrease of multidrug resistance proteins. One of the underlying mechanisms of these effects is the reduction of intracellular and extracellular SOD enzymes by compounds 1, 12 and 14, which render the tumor cells more vulnerable to oxidative stress.

DART - LTQ ORBITRAP as an expedient tool for the identification of synthetic cannabinoids.

Synthetic cannabinoids as designer drugs constitute a major problem due to their rapid increase in number and the difficulties connected with their identification in complex mixtures. DART (Direct Analysis in Real Time) has emerged as an advantageous tool for the direct and rapid analysis of complex samples by mass spectrometry. Here we report on the identification of six synthetic cannabinoids originating from seized material in various matrices, employing the combination of ambient pressure ion source DART and hybrid ion trap - LTQ ORBITRAP mass spectrometer.