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Anton O. Muijsers - One of the best experts on this subject based on the ideXlab platform.
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Assembly of CytoChrome‐C Oxidase in Cultured human Cells
European journal of biochemistry, 1998Co-Authors: Leo G.j. Nijtmans, Jan-willem Taanman, Anton O. Muijsers, Dave Speijer, Coby Van Den BogertAbstract:The assembly of CytoChrome-C Oxidase was studied in human Cells Cultured in the presenCe of inhibitors of mitoChondrial or CytosoliC protein synthesis. MitoChondrial fraCtions were resolved using two-dimensional PAGE (blue native PAGE and triCine/SDS/PAGE) and subsequent western blots were developed with monoClonal antibodies against speCifiC subunits of CytoChrome-C Oxidase. Proteins were also visualized using metaboliC labeling followed by two-dimensional eleCtrophoresis and fluorography. These teChniques allowed identifiCation of two assembly intermediates of CytoChrome-C Oxidase. Assembly of the 13 subunits of CytoChrome-C Oxidase starts with the assoCiation of subunit I with subunit IV. Then a larger subComplex is formed, laCking only subunits VIa and either VIIa or VIIb.
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Presteady-state and steady-state kinetiC properties of human CytoChrome C Oxidase. IdentifiCation of rate-limiting steps in mammalian CytoChrome C Oxidase.
European journal of biochemistry, 1992Co-Authors: André B.p. Van Kuilenburg, Bob F. Van Gelder, Anton C. F. Gorren, Henk L. Dekker, Popko Nieboer, Anton O. MuijsersAbstract:Human CytoChrome C Oxidase was purified in a fully aCtive form from heart and skeletal musCle. The enzyme was seleCtively solubilised with oCtylgluCoside and KCl from submitoChondrial partiCles followed by ammonium sulphate fraCtionation. The presteady-state and steady-state kinetiC properties of the human CytoChrome C Oxidase preparations with either human CytoChrome C or horse CytoChrome C were studied speCtrophotometriCally and Compared with those of bovine heart CytoChrome C Oxidase. The interaCtion between human CytoChrome C and human CytoChrome C Oxidase proved to be highly speCifiC. It is proposed that for effiCient eleCtron transfer to oCCur, a Conformational Change in the Complex is required, thereby shifting the initially unfavourable redox equilibrium. The very slow presteady-state reaCtion between human CytoChrome C Oxidase and horse CytoChrome C suggests that, in this Case, the Conformational Change does not oCCur. The proposed model was also used to explain the steady-state kinetiC parameters under various Conditions. At high ioniC strength (I= 200 mM, pH 7.4), the kCat was highly dependent on the type of Oxidase and it is proposed that the internal eleCtron transfer is the rate-limiting step. The kCat value of the ‘high-affinity’ phase, observed at low ioniC strength (I= 18 mM, pH 7.4), was determined by the CytoChrome C/CytoChrome C Oxidase Combination applied, whereas the Km was highly dependent only on the type of CytoChrome C used. Our results suggest that, depending on the CytoChrome C/CytoChrome C Oxidase Combination, either the dissoCiation of ferriCytoChrome C or the internal eleCtron transfer is the rate-limiting step in the ‘high-affinity’ phase at low ioniC strength. The ‘low-affinity’kCat value was not only determined by the type of Oxidase used, but also by the type of CytoChrome C. It is proposed that the internal eleCtron-transfer rate of the ‘low-affinity’ reaCtion is enhanCed by the binding of a seCond moleCule of CytoChrome C.
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Isoforms of CytoChrome C Oxidase in tissues and Cell lines of the mouse.
Biochimica et biophysica acta, 1992Co-Authors: C. Van Den Bogert, Henk L. Dekker, Pieter A. Bolhuis, J. Cornelissen, A. B. P. Van Kuilenburg, Anton O. MuijsersAbstract:AbstraCt The subunit pattern of immunopurified CytoChrome C Oxidase from Cultured mouse Cells and mature tissues of the mouse was investigated by eleCtrophoretiC analysis. In matrue tissues two forms of CytoChrome C Oxidase Could Clearly be identified on the basis of differenCes in mobility or staining intensity of subunits VIa and VIII. One form was present in musCle and heart, and the other in liver, kidney and spleen. In lung both forms were found. In the thymus, subunit VIII showed the CharaCteristiCs of subunit VIII found in musCle and heart, whereas subunit VIa resembled subunit VIa found in liver. This suggest the existenCe of a third CytoChrome C Oxidase isoform. The subunits of CytoChrome C Oxidase from Cultured Cell lines showed no differenCes between the various Cell lines and resembled those of mature mouse liver tissue. The CytoChrome C Oxidase isoform from Cultured proliferating Cells might therefore be the same as the one found in liver. Alternatively, it might represent either a normally oCCurring fetal isoform, or a form speCifiC for poorly differentiated Cultured Cells.
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Isoforms of human CytoChrome-C Oxidase : subunit Composition and steady-state kinetiC properties
European journal of biochemistry, 1991Co-Authors: André B.p. Van Kuilenburg, Bob F. Van Gelder, Coby Van Den Bogert, Henk L. Dekker, Popko Nieboer, Anton O. MuijsersAbstract:The subunit pattern and the steady-state kinetiCs of CytoChrome-C Oxidase from human heart, musCle, kidney and liver were investigated. PolyaCrylamide gel eleCtrophoresis of immunopurified CytoChrome-C Oxidase preparations suggest that isoforms of subunit VIa exist, whiCh show differenCes in staining intensity and eleCtrophoretiC mobility. No differenCes in subunit pattern were observed between the other nuCleus-enCoded subunits of the various CytoChrome-C Oxidase preparations. Tissue homogenates, in whiCh CytoChrome-C Oxidase was solubilised with laurylmaltoside, were direCtly used in the assays to study the CytoChrome-C Oxidase steady-state kinetiCs. CytoChrome-C Oxidase ConCentrations were determined by immunopurifiCation followed by separation and densitometriC analysis of subunit IV. When studied in a medium of low ioniC strength, the biphasiC kinetiCs of the steady-state reaCtion between human ferroCytoChrome C and the four human CytoChrome-C Oxidase preparations revealed large differenCes for the low-affinity TNmax (maximal turnover number) value, ranging from 77 s-1 for kidney to 273 s-1 for liver CytoChrome-C Oxidase at pH 7.4, I = 18 mM. It is proposed that the low-affinity kinetiC phase refleCts an internal eleCtron-transfer step. For the steady-state reaCtion of human heart CytoChrome-C Oxidase with human CytoChrome C, Km and TNmax values of 9 miCroM and 114 s-1 were found, respeCtively, at high ioniC strength (I = 200 mM, pH 7.4). Only minor differenCes were observed in the steady-state aCtivity of the various human CytoChrome-C Oxidases. The interaCtion between human CytoChrome-C Oxidase and human CytoChrome-C proved to be highly speCifiC. At high ioniC strength, a large deCrease in steady-state aCtivity was observed when reduCed horse, rat or bovine CytoChrome C was used as substrate. Both the steady-state TNmax and Km parameters were strongly affeCted by the type of CytoChrome C used. Our findings emphasize the importanCe of using human CytoChrome C in kinetiC assays performed with tissues from patients with a suspeCted CytoChrome-C Oxidase defiCienCy.
André B.p. Van Kuilenburg - One of the best experts on this subject based on the ideXlab platform.
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Presteady-state and steady-state kinetiC properties of human CytoChrome C Oxidase. IdentifiCation of rate-limiting steps in mammalian CytoChrome C Oxidase.
European journal of biochemistry, 1992Co-Authors: André B.p. Van Kuilenburg, Bob F. Van Gelder, Anton C. F. Gorren, Henk L. Dekker, Popko Nieboer, Anton O. MuijsersAbstract:Human CytoChrome C Oxidase was purified in a fully aCtive form from heart and skeletal musCle. The enzyme was seleCtively solubilised with oCtylgluCoside and KCl from submitoChondrial partiCles followed by ammonium sulphate fraCtionation. The presteady-state and steady-state kinetiC properties of the human CytoChrome C Oxidase preparations with either human CytoChrome C or horse CytoChrome C were studied speCtrophotometriCally and Compared with those of bovine heart CytoChrome C Oxidase. The interaCtion between human CytoChrome C and human CytoChrome C Oxidase proved to be highly speCifiC. It is proposed that for effiCient eleCtron transfer to oCCur, a Conformational Change in the Complex is required, thereby shifting the initially unfavourable redox equilibrium. The very slow presteady-state reaCtion between human CytoChrome C Oxidase and horse CytoChrome C suggests that, in this Case, the Conformational Change does not oCCur. The proposed model was also used to explain the steady-state kinetiC parameters under various Conditions. At high ioniC strength (I= 200 mM, pH 7.4), the kCat was highly dependent on the type of Oxidase and it is proposed that the internal eleCtron transfer is the rate-limiting step. The kCat value of the ‘high-affinity’ phase, observed at low ioniC strength (I= 18 mM, pH 7.4), was determined by the CytoChrome C/CytoChrome C Oxidase Combination applied, whereas the Km was highly dependent only on the type of CytoChrome C used. Our results suggest that, depending on the CytoChrome C/CytoChrome C Oxidase Combination, either the dissoCiation of ferriCytoChrome C or the internal eleCtron transfer is the rate-limiting step in the ‘high-affinity’ phase at low ioniC strength. The ‘low-affinity’kCat value was not only determined by the type of Oxidase used, but also by the type of CytoChrome C. It is proposed that the internal eleCtron-transfer rate of the ‘low-affinity’ reaCtion is enhanCed by the binding of a seCond moleCule of CytoChrome C.
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Isoforms of human CytoChrome-C Oxidase : subunit Composition and steady-state kinetiC properties
European journal of biochemistry, 1991Co-Authors: André B.p. Van Kuilenburg, Bob F. Van Gelder, Coby Van Den Bogert, Henk L. Dekker, Popko Nieboer, Anton O. MuijsersAbstract:The subunit pattern and the steady-state kinetiCs of CytoChrome-C Oxidase from human heart, musCle, kidney and liver were investigated. PolyaCrylamide gel eleCtrophoresis of immunopurified CytoChrome-C Oxidase preparations suggest that isoforms of subunit VIa exist, whiCh show differenCes in staining intensity and eleCtrophoretiC mobility. No differenCes in subunit pattern were observed between the other nuCleus-enCoded subunits of the various CytoChrome-C Oxidase preparations. Tissue homogenates, in whiCh CytoChrome-C Oxidase was solubilised with laurylmaltoside, were direCtly used in the assays to study the CytoChrome-C Oxidase steady-state kinetiCs. CytoChrome-C Oxidase ConCentrations were determined by immunopurifiCation followed by separation and densitometriC analysis of subunit IV. When studied in a medium of low ioniC strength, the biphasiC kinetiCs of the steady-state reaCtion between human ferroCytoChrome C and the four human CytoChrome-C Oxidase preparations revealed large differenCes for the low-affinity TNmax (maximal turnover number) value, ranging from 77 s-1 for kidney to 273 s-1 for liver CytoChrome-C Oxidase at pH 7.4, I = 18 mM. It is proposed that the low-affinity kinetiC phase refleCts an internal eleCtron-transfer step. For the steady-state reaCtion of human heart CytoChrome-C Oxidase with human CytoChrome C, Km and TNmax values of 9 miCroM and 114 s-1 were found, respeCtively, at high ioniC strength (I = 200 mM, pH 7.4). Only minor differenCes were observed in the steady-state aCtivity of the various human CytoChrome-C Oxidases. The interaCtion between human CytoChrome-C Oxidase and human CytoChrome-C proved to be highly speCifiC. At high ioniC strength, a large deCrease in steady-state aCtivity was observed when reduCed horse, rat or bovine CytoChrome C was used as substrate. Both the steady-state TNmax and Km parameters were strongly affeCted by the type of CytoChrome C used. Our findings emphasize the importanCe of using human CytoChrome C in kinetiC assays performed with tissues from patients with a suspeCted CytoChrome-C Oxidase defiCienCy.
Henk L. Dekker - One of the best experts on this subject based on the ideXlab platform.
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purifiCation and CharaCterization of CytoChrome C Oxidase from the inseCt trypanosomatid Crithidia fasCiCulata
Molecular and Biochemical Parasitology, 1996Co-Authors: Dave Speijer, Henk L. Dekker, A O Muijsers, A De Haan, Cornelis K D Breek, Simon P J Albracht, Rob BenneAbstract:CytoChrome C Oxidase was purified from the mitoChondrial lysate of the inseCt trypanosomatid Crithidia fasCiCulata with the aid of a methyl hydrophobiC interaCtion Column in a rapid one-step proCedure. The purified Complex displayed all CharaCteristiCs expeCted from a eukaryotiC CytoChrome C Oxidase: the presenCe of CuA in eleCtron paramagnetiC resonanCe analysis, a CharaCteristiC 605 nm peak in reduCed-minus-oxidized optiCal speCtrosCopy, and the CapaCity to effiCiently oxidize homologous, but not heterologous, CytoChrome C. Two-dimensional PAGE showed that C. fasCiCulata CytoChrome C Oxidase Consists of at least 10 different subunits. N-terminal sequenCes were obtained from the six smallest subunits of the Complex, one of them showing signifiCant similarity to Neurospora Crassa CytoChrome C Oxidase subunit V. The N-terminus of eaCh of the four largest subunits was found to be bloCked.
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Presteady-state and steady-state kinetiC properties of human CytoChrome C Oxidase. IdentifiCation of rate-limiting steps in mammalian CytoChrome C Oxidase.
European journal of biochemistry, 1992Co-Authors: André B.p. Van Kuilenburg, Bob F. Van Gelder, Anton C. F. Gorren, Henk L. Dekker, Popko Nieboer, Anton O. MuijsersAbstract:Human CytoChrome C Oxidase was purified in a fully aCtive form from heart and skeletal musCle. The enzyme was seleCtively solubilised with oCtylgluCoside and KCl from submitoChondrial partiCles followed by ammonium sulphate fraCtionation. The presteady-state and steady-state kinetiC properties of the human CytoChrome C Oxidase preparations with either human CytoChrome C or horse CytoChrome C were studied speCtrophotometriCally and Compared with those of bovine heart CytoChrome C Oxidase. The interaCtion between human CytoChrome C and human CytoChrome C Oxidase proved to be highly speCifiC. It is proposed that for effiCient eleCtron transfer to oCCur, a Conformational Change in the Complex is required, thereby shifting the initially unfavourable redox equilibrium. The very slow presteady-state reaCtion between human CytoChrome C Oxidase and horse CytoChrome C suggests that, in this Case, the Conformational Change does not oCCur. The proposed model was also used to explain the steady-state kinetiC parameters under various Conditions. At high ioniC strength (I= 200 mM, pH 7.4), the kCat was highly dependent on the type of Oxidase and it is proposed that the internal eleCtron transfer is the rate-limiting step. The kCat value of the ‘high-affinity’ phase, observed at low ioniC strength (I= 18 mM, pH 7.4), was determined by the CytoChrome C/CytoChrome C Oxidase Combination applied, whereas the Km was highly dependent only on the type of CytoChrome C used. Our results suggest that, depending on the CytoChrome C/CytoChrome C Oxidase Combination, either the dissoCiation of ferriCytoChrome C or the internal eleCtron transfer is the rate-limiting step in the ‘high-affinity’ phase at low ioniC strength. The ‘low-affinity’kCat value was not only determined by the type of Oxidase used, but also by the type of CytoChrome C. It is proposed that the internal eleCtron-transfer rate of the ‘low-affinity’ reaCtion is enhanCed by the binding of a seCond moleCule of CytoChrome C.
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Isoforms of CytoChrome C Oxidase in tissues and Cell lines of the mouse.
Biochimica et biophysica acta, 1992Co-Authors: C. Van Den Bogert, Henk L. Dekker, Pieter A. Bolhuis, J. Cornelissen, A. B. P. Van Kuilenburg, Anton O. MuijsersAbstract:AbstraCt The subunit pattern of immunopurified CytoChrome C Oxidase from Cultured mouse Cells and mature tissues of the mouse was investigated by eleCtrophoretiC analysis. In matrue tissues two forms of CytoChrome C Oxidase Could Clearly be identified on the basis of differenCes in mobility or staining intensity of subunits VIa and VIII. One form was present in musCle and heart, and the other in liver, kidney and spleen. In lung both forms were found. In the thymus, subunit VIII showed the CharaCteristiCs of subunit VIII found in musCle and heart, whereas subunit VIa resembled subunit VIa found in liver. This suggest the existenCe of a third CytoChrome C Oxidase isoform. The subunits of CytoChrome C Oxidase from Cultured Cell lines showed no differenCes between the various Cell lines and resembled those of mature mouse liver tissue. The CytoChrome C Oxidase isoform from Cultured proliferating Cells might therefore be the same as the one found in liver. Alternatively, it might represent either a normally oCCurring fetal isoform, or a form speCifiC for poorly differentiated Cultured Cells.
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Isoforms of human CytoChrome-C Oxidase : subunit Composition and steady-state kinetiC properties
European journal of biochemistry, 1991Co-Authors: André B.p. Van Kuilenburg, Bob F. Van Gelder, Coby Van Den Bogert, Henk L. Dekker, Popko Nieboer, Anton O. MuijsersAbstract:The subunit pattern and the steady-state kinetiCs of CytoChrome-C Oxidase from human heart, musCle, kidney and liver were investigated. PolyaCrylamide gel eleCtrophoresis of immunopurified CytoChrome-C Oxidase preparations suggest that isoforms of subunit VIa exist, whiCh show differenCes in staining intensity and eleCtrophoretiC mobility. No differenCes in subunit pattern were observed between the other nuCleus-enCoded subunits of the various CytoChrome-C Oxidase preparations. Tissue homogenates, in whiCh CytoChrome-C Oxidase was solubilised with laurylmaltoside, were direCtly used in the assays to study the CytoChrome-C Oxidase steady-state kinetiCs. CytoChrome-C Oxidase ConCentrations were determined by immunopurifiCation followed by separation and densitometriC analysis of subunit IV. When studied in a medium of low ioniC strength, the biphasiC kinetiCs of the steady-state reaCtion between human ferroCytoChrome C and the four human CytoChrome-C Oxidase preparations revealed large differenCes for the low-affinity TNmax (maximal turnover number) value, ranging from 77 s-1 for kidney to 273 s-1 for liver CytoChrome-C Oxidase at pH 7.4, I = 18 mM. It is proposed that the low-affinity kinetiC phase refleCts an internal eleCtron-transfer step. For the steady-state reaCtion of human heart CytoChrome-C Oxidase with human CytoChrome C, Km and TNmax values of 9 miCroM and 114 s-1 were found, respeCtively, at high ioniC strength (I = 200 mM, pH 7.4). Only minor differenCes were observed in the steady-state aCtivity of the various human CytoChrome-C Oxidases. The interaCtion between human CytoChrome-C Oxidase and human CytoChrome-C proved to be highly speCifiC. At high ioniC strength, a large deCrease in steady-state aCtivity was observed when reduCed horse, rat or bovine CytoChrome C was used as substrate. Both the steady-state TNmax and Km parameters were strongly affeCted by the type of CytoChrome C used. Our findings emphasize the importanCe of using human CytoChrome C in kinetiC assays performed with tissues from patients with a suspeCted CytoChrome-C Oxidase defiCienCy.
Michael T. Wilson - One of the best experts on this subject based on the ideXlab platform.
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InteraCtion of CytoChrome-C Oxidase with nitriC oxide.
Methods in enzymology, 1996Co-Authors: Jaume Torres, Michael T. WilsonAbstract:Publisher Summary This Chapter desCribes the methods used to study the interaCtion of nitriC oxide (NO) with isolated CytoChrome-C Oxidase. NO reaCts with fully oxidized or reduCed CytoChrome-C Oxidase (CCO), the final eleCtron aCCeptor of the mitoChondrial respiratory Chain. This enzyme Contains two heme a groups loCated in different protein environments, whiCh Confer on them distinCtive properties giving rise to moieties termed “CytoChrome a” and “CytoChrome a 3 .” The former, in rapid redox equilibrium with CU A (the eleCtron entry site of the enzyme), aCts as an eleCtron transfer protein between CytoChrome C and the binuClear Center, formed by CytoChrome a 3 and CU B , where the oxygen is bound and reduCed. The NO ConCentration may be CalCulated from the stoiChiometry and the volumes of the enzyme and the NO solutions. The use of deoxymyoglobin and ferroCytoChrome-C Oxidase is disCussed in the Chapter. Prior to the titration, CytoChrome-C Oxidase is reduCed with sodium dithionite or in the presenCe of asCorbate and ruthenium hexamine. To monitor the aCtivity of the enzyme CytoChrome C is used as an eleCtron donor, as its reduCed form displays an intense absorption band Centered at 550 nm.
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The oxidation of CytoChrome-C Oxidase vesiCles by hemoglobin
Biochimica et biophysica acta, 1994Co-Authors: Paolo Sarti, Neil Hogg, Victor M. Darley-usmar, Maria Teresa Sanna, Michael T. WilsonAbstract:Human hemoglobin has been used as a pro-oxidant for artifiCial unilamellar phospholipid vesiCles, Containing CytoChrome-C Oxidase inserted into the bilayer. This experimental system was suitable to follow direCtly the kinetiCs of lipid oxidation and the effeCts on both the vesiCle membrane permeability and the funCtional state of CytoChrome-C Oxidase. Following mixing of vesiCles with hemoglobin, an oxygen dependent, peroxyl radiCal mediated, rapid oxidation (taking a few minutes) of the lipid was found to oCCur. On a similar time sCale the membrane beCame ion-leaky and CytoChrome-C Oxidase damaged. The pro-oxidant effeCts of hemoglobin in various oxidation and ligation states were studied and a meChanism, based on a ferriC/ferryl redox CyCle of the heme-iron is proposed to aCCount for these observations.
Andrej Musatov - One of the best experts on this subject based on the ideXlab platform.
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FerriCytoChrome C proteCts mitoChondrial CytoChrome C Oxidase against hydrogen peroxide-induCed oxidative damage.
Free Radical Biology and Medicine, 2010Co-Authors: Erik Sedlák, Marian Fabian, Neal C. Robinson, Andrej MusatovAbstract:AbstraCt An exCess of ferriCytoChrome C proteCts purified mitoChondrial CytoChrome C Oxidase and bound Cardiolipin from hydrogen peroxide-induCed oxidative modifiCation. All of the peroxide-induCed Changes within CytoChrome C Oxidase, suCh as oxidation of Trp 19,IV and Trp 48,VIIC , partial dissoCiation of subunits VIa and VIIa, and generation of Cardiolipin hydroperoxide, no longer take plaCe in the presenCe of ferriCytoChrome C. Furthermore, ferriCytoChrome C suppresses the yield of H 2 O 2 -induCed free radiCal deteCtable by eleCtron paramagnetiC resonanCe speCtrosCopy within CytoChrome C Oxidase. These proteCtive effeCts are based on two meChanisms. The first involves the perOxidase/Catalase-like aCtivity of ferriCytoChrome C, whiCh results in the deComposition of H 2 O 2 , with the apparent bimoleCular rate Constant of 5.1 ± 1.0 M − 1 s − 1 . Although this value is lower than the rate Constant of a speCialized perOxidase, the aCtivity is suffiCient to eliminate H 2 O 2 -induCed damage to CytoChrome C Oxidase in the presenCe of an exCess of ferriCytoChrome C. The seCond meChanism involves ferriCytoChrome C -induCed quenChing of free radiCals generated within CytoChrome C Oxidase. These results suggest that ferriCytoChrome C may have an important role in proteCtion of CytoChrome C Oxidase and Consequently the mitoChondrion against oxidative damage.
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Contribution of peroxidized Cardiolipin to inaCtivation of bovine heart CytoChrome C Oxidase.
Free radical biology & medicine, 2006Co-Authors: Andrej MusatovAbstract:AbstraCt The lipid-soluble peroxides, tert-butyl hydroperoxide and peroxidized Cardiolipin, eaCh reaCt with bovine CytoChrome C Oxidase and Cause a loss of eleCtron-transport aCtivity. CoinCiding with loss of aCtivity is oxidation of Trp19 and Trp48 within subunits VIIC and IV, and partial dissoCiation of subunits VIa and VIIa. tert-Butyl hydroperoxide initiates these struCtural and funCtional Changes of CytoChrome C Oxidase by three meChanisms: (1) radiCal generation at the binuClear Center; (2) direCt oxidation of Trp19 and Trp48; and (3) peroxidation of bound Cardiolipin. All three meChanisms Contribute to inaCtivation sinCe bloCking a single meChanism only partially prevents oxidative damage. The first meChanism is similar to that desCribed for hydrogen peroxide [BioChemistry 43:1003–1009; 2004], while the seCond and third meChanism are unique to organiC hydroperoxides. Peroxidized Cardiolipin inaCtivates CytoChrome C Oxidase in the absenCe of tert-butyl hydroperoxide and oxidizes the same tryptophans within the nuClear-enCoded subunits. Peroxidized Cardiolipin also inaCtivates Cardiolipin-free CytoChrome C Oxidase rather than restoring full aCtivity. Cardiolipin-free CytoChrome C Oxidase, although it does not Contain Cardiolipin, is still inaCtivated by tert-butyl hydroperoxide, indiCating that the other oxidation produCts Contribute to the inaCtivation of CytoChrome C Oxidase. We ConClude that both peroxidized Cardiolipin and tert-butyl hydroperoxide reaCt with and triggers a CasCade of struCtural alterations within CytoChrome C Oxidase. The summation of these events leads to CytoChrome C Oxidase inaCtivation.
