Mitochondrial cytochrome

Mitochondrial cytochrome P450 systems are found in steroidogenic tissues such as adrenal cortex, testis, ovary, and placenta and are concerned with the biosyn-... 

The purpose of sodium nitrite (or amyl nitrite in the absence of IV access) is to produce methemoglobin, which binds cyanide with greater affinity than mitochondrial cytochromes. In the presence of decreased oxygen carrying capacity, as in combined exposures to cyanide and carbon monoxide (e.g., some fires), sodium nitrite can be detrimental and should be avoided. 

Hydrogen sulfide inhibits mitochondrial cytochrome oxidase, resulting in disruption of the electron transport chain and impairing oxidative metabolism. Nervous and cardiac tissues, which have the highest oxygen demand (e.g., brain and heart), are especially sensitive to disruption of oxidative metabolism (Ammann 1986 Hall 1996). 

Biswas SK, Wang L, Yokoyama K et al (2005) Molecular phylogenetics of the genus Trichosporon inferred from mitochondrial Cytochrome b gene sequences. J Clin Microbiol 43 5171-5178... 

Pettersen JC, Cohen SD. 1993. The effects of cyanide on brain mitochondrial cytochrome oxidase and respiratory activities. J Appl Toxicol 13(1) 9-14. 

Mitochondrial cytochrome c is a water-soluble basic protein, residing in the mitochondrial inner membrane where complexes HI and IV of the respiratory chain can reversibly interact with the protein. When the basic protein shuttles between complexes III and IV, cardiolipin facilitates the binding of cytochrome c to cytochrome c oxidase-containing membranes (Salamon and Tollin, 1996). In other words, cytochrome c oxidase in complex IV efficiently receives electrons from cytochrome c only in the presence of cardiolipin. It is well documented that cytochrome c oxidase binds one cardiolipin molecule as an activator and 2 others for anchoring itself to the inner membrane (Awasthi et al, 1971 Suter et al, 2000). 

Axen E, Postlind H, Sjoberg H, Wikvall K. 1994. Liver mitochondrial cytochrome P450 CYP27 and recombinant-expressed human CYP27 catalyze 1 alpha-hydroxylation... 

Bhagwat SV, Boyd MR, Ravindranath V. 1995a. Brain mitochondrial cytochromes P450 xenobiotic metabolism, presence of multiple forms and their selective inducibility. Arch Biochem Biophys 320 73-83. 

Miki H, Takeuchi H, Yamada A, Nishioka M, Matsuzawa Y, et al. 1986. Quantitative analysis of the mitochondrial cytochrome P-450-linked monooxygenase system NADPH-hepatoredoxin reductase, hepatoredoxin, and cytochrome P-450s27 in livers of patients with cerebrotendinous xanthomatosis. Clin Chim Acta 160 255-263. 

M. Fabian and co-workers have studied the protein s role in internal electron transfer to the catalytic center of cytochrome c oxidase using stopped-flow kinetics. Mitochondrial cytochrome c oxidase, CcO, an enzyme that catalyzes the oxidation of ferrocytochrome c by dioxygen, is discussed more fully in Section 7.8. In the overall process, O2 is reduced to water, requiring the addition of four electrons and four protons to the enzyme s catalytic center. Electrons enter CcO from the cytosolic side, while protons enter from the matrix side of the inner mitochondrial membrane. This redox reaction. 

However in the absence of O2, anaerobic glycolysis—fermentation—produces only 2 mol of ATP per mol of glucose consumed. In the absence of O2 the mitochondrial cytochrome chain ceases to operate and as a resnlt NADH2 accumnlates... 

Figure 6.1 Pathways involved in glucose oxidation by plant cells (a) glycolysis, (b) Krebs cycle, (c) mitochondrial cytochrome chain. Under anoxic conditions. Reactions 1, 2 and 3 of glycolysis are catalysed by lactate dehydrogenase, pyruvate decarboxylase and alcohol dehydrogenase, respectively. ATP and ADP, adenosine tri- and diphosphate NAD and NADHa, oxidized and reduced forms of nicotinamide adenine dinucleotide PGA, phosphoglyceraldehyde PEP, phosphoenolpyruvate Acetyl-CoA, acetyl coenzyme A FP, flavoprotein cyt, cytochrome e, electron. (Modified from Fitter and Hay, 2002). Reprinted with permission from Elsevier...

A). Cyanide ions (CN ) enter the organism in the form of hydrocyanic acid (HCN) the latter can be inhaled, released from cyanide salts in the acidic stomach juice, or enzymatically liberated from bitter almonds in the gastrointestinal tract The lethal dose of HCN can be as low as 50 mg. CN binds with high affinity to trivalent iron and thereby arrests utilization of oxygen via mitochondrial cytochrome oxidases of the respiratory chain An internal asphyxiation (histotoxic hypoxia) ensues while erythrocytes remain charged with O2 (venous blood colored bright red). 

Jana NR, Zemskov EA, Wang G, and Nukina N (2001) Altered proteasomal function due to the expression of polyglutamine-expanded truncated N-terminal huntingtin induces apoptosis by caspase activation through mitochondrial cytochrome c release. Hum. Mol. Genet. 10 1049-1059. 

Most cases of intoxication from industrial exposure have been mild, with rapid onset of eye irritation, headache, sneezing, and nausea weakness, light-headedness, and vomiting may also occur. Acute exposure to high concentrations may produce profound weakness, asphyxia, and death. Acrylonitrile is metabolized to cyanide by hepatic microsomal reactions. Deaths from acute poisoning result from inhibition of mitochondrial cytochrome oxidase activity by metabolically liberated cyanide. Inhalation of more moderate concentrations for a longer period of time leads to damage to the liver tissues in addition to central nervous system (CNS) effects. ... 

Q Yang, X-Y Liu, M Hara, P Lundahl, J Miyake. Quantitative affinity chromatographic studies of mitochondrial cytochrome c binding to bacterial photosynthetic reaction center, reconstituted in liposome membranes and immobilized by detergent dialysis and avidin-biotin binding. Anal Chem 280 94-102, 2000. 

E. Humpfer, L. Yu, C. A. Yu, C. Griesinger, U. Brandt, Three molecules of ubiquinone bind specifically to mitochondrial cytochrome bct complex, J. Biol. Chem., 2001, 276, 35231-35234. 

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