Emanuele De Nitto

Learn More
A study is presented on the coupling of electron transfer with proton transfer at heme a and Cu(A) (redox Bohr effects) in carbon monoxide inhibited cytochrome c oxidase isolated from bovine heart mitochondria. Detailed analysis of the coupling number for H(+) release per heme a, Cu(A) oxidized (H(+)/heme a, Cu(A) ratio) was based on direct measurement of(More)
A study is presented of the ----H+/e- stoichiometry for H+ pumping by the cytochrome chain in isolated rat liver mitochondria under level-flow and steady-state conditions. It is shown that the ----H+/e- stoichiometry for the cytochrome chain varies under the influence of the flow rate and transmembrane delta microH+. The rate-dependence is shown to be(More)
Dietary choline deprivation (CD) is associated with behavioral changes, but mechanisms underlying these detrimental effects are not well characterized. For instance, no literature data are available concerning the CD effects on brain mitochondrial function related to impairment in cognition. Therefore, we investigated brain mitochondrial function and redox(More)
A study is presented of the factors affecting the H+/e- stoichiometry of the proton pump of mitochondrial cytochrome c oxidase, isolated and reconstituted in phospholipid vesicles (COV). Under level flow conditions, i.e., in the absence of a transmembrane delta muH+, the H+/e- ratio, obtained from spectrophotometric measurements of the initial rates of(More)
The H+/e- stoichiometry of protonmotive cytochrome c oxidase, isolated from bovine heart mitochondria and reconstituted in liposomes, has been determined by making use of direct spectrophotometric measurements of the initial rates of e- flow and H+ translocation. It is shown that the ----H+/e- ratio for redox-linked proton ejection by the oxidase varies(More)
The role of supernumerary subunits of bovine heart cytochrome c oxidase has been investigated by examining the effect on the enzymatic activity of limited proteolysis by chymotrypsin, thermolysin, and trypsin. All three proteases, when added to the soluble oxidase, digested subunits III, VIa, and VIb and caused inhibition of electron flow in the oxidase. In(More)
In the last few years, evidence has accumulated supporting the applicability of the cooperative model of proton pumps in cytochrome systems, vectorial Bohr mechanisms, to heme-copper oxidases. The vectorial Bohr mechanism is based on short- and long-range protonmotive cooperative effects linked to redox transitions of the metal centers. The crystal(More)
A study is presented on proton transfer associated with the reaction of the fully reduced, purified bovine heart cytochrome c oxidase with molecular oxygen or ferricyanide. The proton consumption associated with aerobic oxidation of the four metal centers changed significantly with pH going from approximately 3.0 H(+)/COX at pH 6.2-6.3 to approximately 1.2(More)
A study is presented on the morphology and respiratory functions of mitochondria from Torpedo marmorata red blood cells. In vivo staining of red blood cells and transmission electron microscopy showed the existence of a considerable number of vital and orthodox mitochondria which decreased from young erythroblasts to mature erythrocytes from 60-50 to 30-20(More)
A study is presented on the pH dependence of proton translocation in the oxidative and reductive phases of the catalytic cycle of purified cytochrome c oxidase (COX) from beef heart reconstituted in phospholipid vesicles (COV). Protons were shown to be released from COV both in the oxidative and reductive phases. In the oxidation by O2 of the fully reduced(More)