Implication Of Cytochrome Research Articles

Myopathy with MTCYB mutation mimicking Multiple Acyl-CoA Dehydrogenase Deficiency

We describe two patients with mitochondrial DNA mutations in the gene encoding cytochrome b (m.15579A>G, p.Tyr278Cys and m.15045G>A p.Arg100Gln), which presented as a pure myopathic form (exercise intolerance), with an onset in childhood. Diagnosis was delayed, because acylcarnitine profile showed an increase in medium and long-chain acylcarnitines, suggestive of multiple acyl-CoA dehydrogenase deficiency, riboflavin transporter deficiency or FAD metabolism disorder. Implication of cytochrome b in fatty acid oxidation, and physiopathology of the mutations are discussed.

Mechanisms of action for light therapy: A review of molecular interactions

Five decades after the first documented use of a laser for wound healing, research in light therapy has yet to elucidate the underlying biochemical pathways causing its effects. The aim of this review is to summarize the current research into the biochemical mechanisms of light therapy in order to better direct future studies. The implication of cytochrome c oxidase as the photoacceptor modulating light therapy is reviewed, as are the predominant hypotheses of the biochemical pathways involved in the stimulation of wound healing, cellular proliferation, production of transcription factors and other reported stimulatory effects.

Mitochondrial genome analysis of Ochotona curzoniae and implication of cytochrome c oxidase in hypoxic adaptation

Pikas originated in Asia and are small lagomorphs native to cold climates. The plateau pika, Ochotona curzoniae is a keystone species on the Qinghai–Tibet Plateau and an ideal animal model for hypoxic adaptation studies. Altered mitochondrial function, especially cytochrome c oxidase activity, is an important factor in modulation of energy generation and expenditure during cold and hypoxia adaptation. In this study, we determined the complete nucleotide sequence of the O. curzoniae mitochondrial genome. The plateau pika mitochondrial DNA is 17,131 bp long and encodes the complete set of 37 proteins typical for vertebrates. Phylogenetic analysis based on concatenated heavy-strand encoded protein-coding genes revealed that pikas are closer to rabbit and hare than to rat. This suggests that rabbit or hare would be a good control animal for pikas in cold and hypoxia adaptation studies. Fifteen novel mitochondrial DNA-encoded amino acid changes were identified in the pikas, including three in the subunits of cytochrome c oxidase. These amino acid substitutions potentially function in modulation of mitochondrial complexes and electron transport efficiency during cold and hypoxia adaptation.

Cytochrome c oxidase subunit IV as a marker of protein kinase Cepsilon function in neonatal cardiac myocytes: implications for cytochrome c oxidase activity.

We have previously demonstrated that low concentrations of phorbol esters stimulate the selective translocation of protein kinase C (PKC) alpha and epsilon from the cell soluble to the particulate fraction in NCMs (neonatal rat cardiac myocytes). We therefore determined if the in vitro phosphorylation of substrates in these fractions could be used as assays of PKCalpha or epsilon activation. Intact cell phorbol ester treatment caused a decline in the in vitro (32)P-incorporation into several proteins in the cell-soluble fraction. These declines occurred in the presence or absence of in vitro Ca(2+) and probably reflected the exit of PKC isoenzymes from the soluble fraction. In contrast, an approx. 18 kDa protein incorporated (32)P in particulate fractions isolated from 4beta-PMA-treated cells in a Ca(2+)-independent manner. Proteomic and immunoprecipitation analyses indicated that the protein is subunit IV of the cytochrome c oxidase complex (COIV). In vitro phosphorylation of COIV was attenuated by PKC pseudosubstrate peptides. Introduction of an PKCepsilon-selective translocation inhibitor [Johnson, Gray, Chen and Mochly-Rosen (1996) J. Biol. Chem. 271, 24962-24966] into NCMs before 4beta-PMA treatments also attenuated the in vitro phosphorylation of COIV. In mitochondrial extracts from 4beta-PMA-treated NCMs, the PKCepsilon isoenzyme coimmunoprecipitated with COIV, and cytochrome c oxidase activity was enhanced 2-fold. The in vitro phosphorylation of COIV reflects a novel approach for monitoring PKCepsilon function in NCMs. Furthermore, PKCepsilon probably interacts with COIV in NCM mitochondria to enhance electron-transport chain complex IV activity.

Synthesis, characterization of heterodinuclear Co‐Cu complex and its electrocatalytic activity towards O2 reduction: Implications for cytochrome c oxidase active site modeling

AbstractA new dinucleating ligand consisting of a tetraphenylporphyrin derivative covalently linked with tris(2‐benzimidazylmethyl)‐amine and its homodinuclear Co‐Co and heterodinuclear Co‐Cu complexes were synthesized and spectroscopically characterized. The heterobimetallic cobalt‐copper complex bearing three benzimidazole ligands for copper, as cytochrome c oxidase active site model, was applied to the surface of glassy carbon electrode to show electrocatalytic activity for O2 reduction in aqueous solution at an acidity level close to physiological pH value. The kinetic parameters of this electrocatalytic process were obtained.

Zn(II), Ni(II), Cu(II), and Fe(III) complexes of potentially bimetalating tris(pyridine- and imidazole-appended) picket-fence naphthylporphyrins with benzyl ether spacers: implications for cytochrome c oxidase active-site modeling.

Two new unsymmetrical picket-fence naphthylporphyrin ligands, 1 and 2, and several of their metalated porphyrinato complexes have been synthesized as precursor model compounds for the binuclear (Fe/Cu) cytochrome c oxidase (CcO) active site. 1 and 2 have a naphthylporphyrin superstructure that has been specifically incorporated to confer long-term configurational stability to the atropisomeric products. The two picket-fence porphyrin ligands also bear covalently linked, axially offset tris(heterocycle) coordination sites for a copper ion, much like that found in the native enzyme. Monometallic porphyrin complexes [M = Zn(II), Ni(II), Cu(II), and Fe(III)] of the pyridine-appended ligand 1 have been prepared and spectroscopically and magnetically characterized. An unusual monomeric iron(III) hydroxo porphyrin complex was isolated upon workup of the compound formed under ferrous sulfate/acetic acid reflux conditions. There is general difficulty in forming binuclear complexes of 1, which is attributed to the conformational flexibility of the benzyl ether type picket spacers. The potential of ligands such as 1 and 2 for future CcO active-site modeling studies is considered.

Implications of cytochrome b sequence variation for biogeography and conservation of the northern flying squirrels (Glaucomys sabrinus) of the Alexander Archipelago, Alaska

The Alexander Archipelago of southeast Alaska is a highly fragmented landscape that is suspected to support a relatively large number of endemic mammals. At least two subspecies of northern flying squirrels (Glaucomys sabrinus) have been recognized from the region, the endemic Prince of Wales Island flying squirrel, Glaucomys sabrinus griseifrons, and the Alaska Coast flying squirrel, G. s. zaphaeus. We examined 56 northern flying squirrels from Alaska, Washington State, and Yukon Territory, using the DNA sequence from the mitochondrial cytochrome b gene to assess geographic variation. Flying squirrels from Washington were highly divergent (7.3%) from those of Alaska and Yukon Territory. Variation among Alaska and Yukon Territory populations was minimal, but five haplotypes were found. One predominantly "mainland" haplotype was widespread throughout Alaska, one island haplotype was confined to nine islands in southeast Alaska ("Prince of Wales complex"), and three haplotypes were unique. Flying squirrels of the Prince of Wales complex appear to be neoendemics and descended from a single founder population. Mitochondrial variation, although minimal, is consistent with the continued recognition of G. s. griseifrons. Our results, in light of increased habitat fragmentation in southeast Alaska, suggest that molecular data can provide important base-line information for effective management of insular populations.

Implications of cytochrome <i>b</i> sequence variation for biogeography and conservation of the northern flying squirrels (<i>Glaucomys sabrinus</i>) of the Alexander Archipelago, Alaska

Implications of cytochrome <i>b</i> sequence variation for biogeography and conservation of the northern flying squirrels (<i>Glaucomys sabrinus</i>) of the Alexander Archipelago, Alaska

Association of cytochrome b translational activator proteins with the mitochondrial membrane: implications for cytochrome b expression in yeast

The products of the nuclear genes CBS1 and CBS2 are both required for translational activation of mitochondrial apocytochrome b in yeast. We report the intramitochondrial localization of both proteins by use of specific antisera. Based on its solubilization properties the CBS1 protein is presumed to be a component of the mitochondrial membrane; the detergent concentrations needed to release CBS1 from mitochondria are almost the same as for cytochrome c1. In contrast, CBS2 behaves like a soluble protein, with some characteristics of a membrane-associated protein. A model is presented for translational activation of cytochrome b, which might also be applicable to translational regulation of other mitochondrial genes.