Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.9.3.1 (cytochrome oxidase)
 8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytochrome oxidase forms two distinctive compounds with oxygen at --105 and --90 degrees C, one appears to be oxycytochrome oxidase (Compound A) and the other peroxycytochrome oxidase (Compound B). The functional role of compound B in the oxidation of cytochrome c has been examined in a variety of mitochondrial preparations. The rate and the extent of the reaction have been found to be dependent upon the presence of a fluid phase in the vicinity of the site of the reaction of cytochrome c and cytochrome oxidase. The kinetics of cytochrome c oxidation and of the slowly reacting component of cytochrome oxidase are found to be linked to one another even in cytochrome c depleted preparations, but under appropriate conditions, especially low temperatures, the oxidation of cytochrome c precedes that of this component of cytochrome oxidase. Based upon the identification of the slowly reacting components of cytochrome oxidase with cytochrome c, various mechanisms are considered which allow cytochrome c to be oxidized without the intervention of cytochrome a at very low temperatures, and tunneling seems an appropriate mechanism.
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PMID:Cytochrome c-cytochrome oxidase interaction at subzero temperatures. 20 1

Reaction of O2 and CO with a caa3-type terminal cytochrome oxidase (EC 1.9.3.1) from the thermophilic bacterium PS3 grown with high aeration was studied at low temperatures. The CO recombination at the temperature range studied (-50 degrees C to -80 degrees C) followed first-order kinetics with an activation energy of 29.3 kJ/mol (7.0 kcal/mol). In the presence of O2 at -113 degrees C the photolysed reduced form binds O2 to form an 'oxy' intermediate similar to Compound A. At a higher temperature (-97 degrees C) another intermediate, similar to Compound B, is formed as a result of electron transfer from the enzyme to the liganded O2.
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PMID:Reaction of caa3-type terminal cytochrome oxidase from the thermophilic bacterium PS3 with oxygen and carbon monoxide at low temperatures. 608 42

Receptors for glucocorticoid (GR) and corticotropin-releasing hormone (CRH) are largely found in brain sensorimotor structures, particularly in cerebellum, underlining a potential role of stress hormones in the regulation of motor function. Since CRH is involved in neuroplasticity, known for its trophic effect on synapses, we investigated how manipulations in corticosterone serum levels can modulate the CRH system in the cerebellum and affect motor coordination. Corticosterone at doses of either 15 or 30mg/kg was injected in mice and the status of hormonal expression evaluated in cerebellum, hippocampus, and hypothalamus in undisturbed housing conditions or after different behavioral tests. Under both conditions, metabolic activity in numerous brain regions involved in motor functions and emotion was measured by means of cytochrome oxidase (COX) activity labeling. After six consecutive days of corticosterone administration, CRH-R1 transcription was downregulated in hypothalamic and cerebellar regions and hypometabolic changes were observed in mice treated with the higher dose for several limbic and sensorimotor circuitries, notably basal ganglia, deep cerebellar nuclei, and red nucleus. Corticosterone did not modify motor activity, anxiety, and spatial orientation, but decreased latencies before falling from the rotorod and prevented mice from reaching targets in the coat-hanger test. In addition, COX activities were similar to control mice except in ventromedial thalamus and dorsal neostriatum, possibly indicating that physical activity protected brain energy metabolism against the stress hormone. The present findings showed that the CRH/CRH-R1 system might play a role in mediating the effects of stress on cerebellar function, affecting especially motor learning tasks.
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PMID:Repeated corticosterone injections in adult mice alter stress hormonal receptor expression in the cerebellum and motor coordination without affecting spatial learning. 2826 30