ライフサイエンスコーパス: ubiquinol

1 conserving role coupled to the oxidation of ubiquinol.

2 takes up a proton, possibly sharing it with ubiquinol.

3 te to allow reduction of the Fe-S protein by ubiquinol.

4 as 1.23 times that of the membrane permeable ubiquinol.

5 ptosis defense in mitochondria by generating ubiquinol.

6 idues altered the affinity of the enzyme for ubiquinol.

7 stoquinol but increases with temperature for ubiquinol.

8 x in the absence of the exogenous substrate, ubiquinol.

9 tics of ISP and cytochrome b(L) reduction by ubiquinol.

10 detected at the Qp site during oxidation of ubiquinol.

11 (QL): an increase in the KM of the substrate ubiquinol-1 (up to 4-fold) and an increase in the appare

12 more, at high concentrations, the substrates ubiquinol-1 and ubiquinol-2 inhibit turnover in an uncom

13 ctroscopy and by determining the activity of ubiquinol-1 oxidase.

14 In each case, the Km for ubiquinol-1 was determined as a measure of possible pert

15 mutant that had a noticeably altered Km for ubiquinol-1 was W136A, in which the Km was about sixfold

16 cilla phospholipids, it was reduced by Q1H2 (ubiquinol-1) but not by ascorbate/TMPD (N,N,N',N'-tetram

17 its oxygen reduction rate in the presence of ubiquinol-1.

18 We demonstrate that ubiquinol-10 dissociation is not rate determining and de

19 parameters (K(m) and V(max)) with respect to ubiquinol-10 have been determined.

20 the lipophilic nature of the AOX substrate (ubiquinol-10) has hindered its kinetic characterisation

21 was achieved via native ubiquinol-8 or added ubiquinol-10, and impedance spectroscopy was used to cha

22 was achieved via native ubiquinol-8 or added ubiquinol-10, and impedance spectroscopy was used to cha

23 bic antioxidants such as alpha-tocopherol or ubiquinol-10.

24 se cytochrome bo3 from Escherichia coli with ubiquinol-2 (UQ2H2) was carried out using substoichiomet

25 ncentrations, the substrates ubiquinol-1 and ubiquinol-2 inhibit turnover in an uncompetitive fashion

26 Using analogs of the respiratory substrates ubiquinol-3 and rhodoquinol-3, we show that the relative

27 of the heme-copper superfamily that utilizes ubiquinol-8 (Q8H2) as a substrate.

28 d expression, or in the riboflavin (ribE) or ubiquinol-8 (ubiH) biosynthetic pathway, which leads to

29 and catalyzes the two-electron oxidation of ubiquinol-8 and four-electron reduction of O(2) to water

30 and catalyzes the two-electron oxidation of ubiquinol-8 and four-electron reduction of O2 to water.

31 nal oxidases that catalyses the oxidation of ubiquinol-8 and the reduction of oxygen to water.

32 ron transfer to cbo3 was achieved via native ubiquinol-8 or added ubiquinol-10, and impedance spectro

33 on transfer to cbo 3 was achieved via native ubiquinol-8 or added ubiquinol-10, and impedance spectro

34 ratory chain, reducing O2 to water and using ubiquinol-8 or menaquinol-8 as its immediate reductant.

35 cbo(3) is mediated by the membrane-localized ubiquinol-8, the physiological electron donor of cbo(3).

36 ial inner membrane by reducing ubiquinone to ubiquinol (a radical-trapping antioxidant with anti-ferr

37 aprotic medium to probe the oxidation of the ubiquinol analogue, 2,3-dimethoxy-5-methyl-1,4-benzoquin

38 se temperature dependence of the KIE for the ubiquinol analogue.

39 e structural similarities of the heme-copper ubiquinol and cytochrome c oxidase complexes suggest the

40 as essential for electron transfer from both ubiquinol and menaquinol to NapAB.

41 cture and electrochemical properties between ubiquinol and menaquinol.

42 ts (KIEs) at 296 K are 1.87 and 3.45 for the ubiquinol and plastoquinol analogues, respectively, and

43 oxidase that accepts electrons directly from ubiquinol and reduces oxygen to water without involving

44 o ubiquinone, resulting in the generation of ubiquinol and the regeneration of the NAD+ and FAD cofac

45 i, except that it uses menaquinol instead of ubiquinol as a substrate.

46 The apparent K(m) for ubiquinol at the Q(o) site in the presence of proximal Q

47 bc(1) complex is the bifurcated oxidation of ubiquinol at the Qp site.

48 and FAD cofactors, and complex III oxidizes ubiquinol back to ubiquinone, which also serves as an el

49 contains residues thought to be involved in ubiquinol binding.

50 ditions and the possible roles of ubiquinone/ubiquinol binding/dissociation in energy conversion.

51 hus, W136 may be at or close to a substrate (ubiquinol)-binding site in cytochrome bo3.

52 structures, these results suggest substrate ubiquinol binds in a fashion similar to that of stigmate

53 quinone binds to only the reduced enzyme and ubiquinol binds to only the oxidized enzyme is shown to

54 -state turnover of the cyt bc1 complex using ubiquinol, but not plastoquinol, as a substrate, leading

55 ee more O(2)(*) generation upon oxidation of ubiquinol by a high potential oxidant, such as cytochrom

56 the yeast cytochrome bc(1) complex oxidizes ubiquinol by an alternating, half-of-the-sites mechanism

57 at generation of O-2 during the oxidation of ubiquinol by the cytochrome bc1 complex results from a l

58 The putative oxidation of ubiquinol by the cytochrome bo3 terminal oxidase of Esch

59 oint potential, confirming that oxidation of ubiquinol by the iron-sulfur protein is the rate-limitin

60 Q(P) pocket through bifurcated oxidation of ubiquinol by transferring its two electrons to a high po

61 s thus inferred that sequential oxidation of ubiquinol (by two sequential n=1 processes) is more rapi

62 When modeled in this way, mucidin and ubiquinol can bind simultaneously to the Q(o) site with

63 dition, mitochondrion-specific antioxidants, ubiquinol conjugated to triphenyl phosphonium, triphenyl

64 nalysis identified ATP synthase gamma chain, ubiquinol-cyt-C reductase, heat shock protein 10 (Hsp10)

65 Ubiquinol cytochrome c oxido-reductase (EC. 1.10.2.2, bc

66 Ubiquinol cytochrome c oxidoreductase (bc1 complex) serv

67 It encodes a 6.6-kD homolog of mitochondrial ubiquinol cytochrome c oxidoreductase (QCR9), subunit 9

68 hly conserved C-terminal domain comprising a ubiquinol-cytochrome c chaperone region.

69 The interaction of cytochrome c with ubiquinol-cytochrome c oxidoreductase (bc complex) has b

70 Cytochrome c(1) of Rhodobacter sphaeroides ubiquinol-cytochrome c oxidoreductase contains several i

71 mes (aconitase, succinate dehydrogenase, and ubiquinol-cytochrome c oxidoreductase), as well as cytos

72 re stoichiometric inhibitors of complex III (ubiquinol-cytochrome c oxidoreductase), exerting their h

73 in the Rieske iron-sulfur subunit (Rip1) of ubiquinol-cytochrome c reductase (bc1) accumulate a late

74 Ubiquinol-cytochrome c reductase activities of mitochond

75 Ubiquinol-cytochrome c reductase activities of the bc(1)

76 xes (F195Y, F195H, or F195W) having the same ubiquinol-cytochrome c reductase activity as the wild-ty

77 ounced decrease in efficacy of inhibition of ubiquinol-cytochrome c reductase activity by stigmatelli

78 A have, respectively, 78%, 100%, and 100% of ubiquinol-cytochrome c reductase activity found in the w

79 Antimycin stimulated the ubiquinol-cytochrome c reductase activity of the bc(1) c

80 nker region of the Rieske protein lowers the ubiquinol-cytochrome c reductase activity of the mitocho

81 Ilicicolin inhibits ubiquinol-cytochrome c reductase activity of the yeast b

82 ron leakage to oxygen and thus decreases the ubiquinol-cytochrome c reductase activity.

83 e iron-sulfur protein restores 25-30% of the ubiquinol-cytochrome c reductase activity.

84 Out of these, the ubiquinol-cytochrome c reductase core II protein (UQCRC2

85 c.941A>C (p.Tyr314Ser) in the mitochondrial ubiquinol-cytochrome c reductase core protein 1 (UQCRC1)

86 alize with the mitochondrial matrix protein, ubiquinol-cytochrome c reductase core protein 2 or the i

87 se Core Subunit S1, Succinate dehydrogenase, Ubiquinol-Cytochrome C Reductase Core Protein 2, Cytochr

88 Ubiquinol-cytochrome c reductase hinge protein (UQCRH) i

89 The final step in the assembly of the ubiquinol-cytochrome c reductase or bc(1) complex involv

90 n FeS cluster assembly and newly synthesized ubiquinol-cytochrome c reductase Rieske iron-sulfur poly

91 1a, NADH dehydrogenaseB2, and the AAA ATPase Ubiquinol-cytochrome c reductase synthesis1), and intera

92 bilizes the interaction of COX with the bc1 (ubiquinol-cytochrome c reductase) complex.

93 actions between mitochondrial complexes III (ubiquinol-cytochrome c reductase; cyt. bc1) and IV (cyto

94 tallographic structures of the mitochondrial ubiquinol/cytochrome c oxidoreductase (cytochrome bc(1)

95 The mitochondrial cytochrome bc(1) complex (ubiquinol/cytochrome c oxidoreductase) is generally thou

96 he reduction of the bis-heme cytochrome b of ubiquinol: cytochrome c oxidoreductase (complex III, bc1

97 eactions of the bis-heme cytochrome b of the ubiquinol:cytochrome c oxidoreductase complex (complex I

98 is was reduced in respiratory complexes III (ubiquinol:cytochrome c oxidoreductase) and IV (cytochrom

99 fic inhibitor of the cytochrome bc1 complex (ubiquinol:cytochrome c oxidoreductase), blocked almost c

100 Ubiquinol:cytochrome c oxidoreductase, bc1 complex, is t

101 Cytochrome bc(1) complexes are ubiquinol:cytochrome c oxidoreductases, and as such, the

102 the Rieske iron-sulfur protein (ISP) of the ubiquinol:cytochrome c(2) oxidoreductase (bc(1) complex)

103 Cells lacking oxygen reduction accumulate ubiquinol, driving the succinate dehydrogenase (SDH) com

104 ll ubiquinone would be completely reduced to ubiquinol, e.g., by the sulfidequinone oxidoreductase, b

105 t on the dynamic processes of the ubiquinone/ubiquinol exchange mechanism in complex I and the Q-cycl

106 However, how ubiquinone/ubiquinol exchange occurs on catalytically relevant time

107 Hence, the protons required for ubiquinol formation must be taken up from the outside of

108 lts from a leakage of the second electron of ubiquinol from its Q cycle electron transfer pathway to

109 ble to oxidize both reduced cytochrome c and ubiquinol in a cyanide sensitive manner.

110 gest that there is only one binding site for ubiquinol in cyt bo3 and that site corresponds to the QH

111 these proteins allow electron transfer from ubiquinol in cytochrome bc(1) to oxygen in cytochrome cb

112 dase catalyzes the two-electron oxidation of ubiquinol in the cytoplasmic membrane of Escherichia col

113 c(1) reduced by several equivalents of decyl-ubiquinol in the presence of antimycin corresponded to o

114 anion (O(2)(*)) generation upon oxidation of ubiquinol in the presence of molecular oxygen.

115 one yet shows the position of the substrate, ubiquinol, in the quinol oxidase (Q(o)) site.

116 by a protonmotive Q cycle mechanism in which ubiquinol is oxidized at one center in the enzyme, refer

117 In this model, ubiquinol is oxidized at one site and ubiquinone is redu

118 t step, ubiquinone is bound and reduced, and ubiquinol is released.

119 hydrochloride-O2* adduct during oxidation of ubiquinol, is 3 times higher in the F195A complex than i

120 case that all ubiquinone has been reduced to ubiquinol its reoxidation by Cox2 will enable the cytoch

121 ical inhibition of the ETC complex I reduces ubiquinol levels while decreasing ATP levels and activat

122 uggests that the reduced form of ubiquinone (ubiquinol) may also function as a lipid soluble antioxid

123 t with electron transfer mechanisms in which ubiquinol must simultaneously interact with the iron-sul

124 Ubiquinol or coenzyme Q (CoQ) is a lipid-soluble electro

125 ons in which concentration of one substrate (ubiquinol or ISP(ox)) was saturating and the other was v

126 talyzes the two-electron oxidation of either ubiquinol or menaquinol in the membrane and scavenges O2

127 m = 2-(2-pyridyl)benzimidazolate) oxidizes a ubiquinol or plastoquinol analogue in acetonitrile.

128 ations except R391K result in enzyme lacking ubiquinol oxidase activity.

129 The cytochrome bo3 ubiquinol oxidase catalyzes the two-electron oxidation o

130 The cytochrome bo3 ubiquinol oxidase complex from Escherichia coli contains

131 translocation mechanism for the heme-copper ubiquinol oxidase complexes should be further investigat

132 The cytochrome bo3 ubiquinol oxidase contains at least one and possibly two

133 The purified Escherichia coli cytochrome bo3 ubiquinol oxidase contains four subunits that are each i

134 The ubiquinol oxidase cytochrome bo3 from Escherichia coli i

135 rolled by regB-regA, fnrL, and hvrA and that ubiquinol oxidase expression is controlled by regB-regA,

136 The R481 residue of cytochrome bo(3) ubiquinol oxidase from E. coli is highly conserved in th

137 The cytochrome bo3 ubiquinol oxidase from Escherichia coli resides in the b

138 The cytochrome bo(3) ubiquinol oxidase from Escherichia coli resides in the b

139 5)N isotope labeling of the cytochrome bo(3) ubiquinol oxidase from Escherichia coli with auxotrophs

140 An ubiquinol oxidase from Escherichia coli, cytochrome bo(3

141 very close homologue of the cytochrome bo(3) ubiquinol oxidase from Escherichia coli, except that it

142 ive ubiquinone-10 substrate and an auxiliary ubiquinol oxidase from Trypanosoma brucei brucei.

143 lls harbouring CpcA-labelled cytochrome bd 1 ubiquinol oxidase in the cytoplasmic membrane show that

144 Cytochrome bo (3) ubiquinol oxidase is a transmembrane protein, which oxid

145 Vitreoscilla cytochrome bo ubiquinol oxidase is similar in some properties to the E

146 ults were obtained for cytochrome bo(3), the ubiquinol oxidase of Escherichia coli.

147 cytochrome b to restore an apparently normal ubiquinol oxidase site, but that interaction between the

148 teraction of Rc_sR42 with cydA (cytochrome d ubiquinol oxidase subunit I).

149 native oxidase (AOX) is a non-proton-pumping ubiquinol oxidase that catalyzes the reduction of oxygen

150 idase (AOX) in plants is a non-proton-motive ubiquinol oxidase that is activated by redox mechanisms

151 s a cytochrome bcc:aa(3) and a cytochrome bd ubiquinol oxidase that require a combined approach to bl

152 brane of Escherichia coli, overexpressing an ubiquinol oxidase, cytochrome bo 3 (cbo 3), was "tethere

153 brane of Escherichia coli, overexpressing an ubiquinol oxidase, cytochrome bo3 (cbo3), was "tethered"

154 r aerobic respiration, cytochrome cbb(3) and ubiquinol oxidase.

155 ncodes a microaerobically-expressed bb3-type ubiquinol oxidase.

156 h-affinity Q(H) site in the cytochrome bo(3) ubiquinol oxidase.

157 gues of the heme/Cu site in cytochrome c and ubiquinol oxidases has been studied in aqueous buffers.

158 ly controls synthesis of cytochrome cbb3 and ubiquinol oxidases that function as terminal electron ac

159 nce for conformational communication between ubiquinol oxidation (center P) and ubiquinone reduction

160 chrome b(H) complexes at center N and favors ubiquinol oxidation at center P by increasing the amount

161 and high potential redox components control ubiquinol oxidation at center P, consistent with the pro

162 acrylate stilbene, two inhibitors that block ubiquinol oxidation at center P, inhibit the yeast enzym

163 es, have allowed us to demonstrate that: (i) ubiquinol oxidation at the Qo-site of the bc1 complex ha

164 Although direct ubiquinol oxidation by Cox2 conserves less energy than u

165 hrome c oxidation by a cytochrome c oxidase, ubiquinol oxidation by Cox2 is of advantage when all ubi

166 oxidation by Cox2 conserves less energy than ubiquinol oxidation by the cytochrome bc(1) complex foll

167 of b reduction is dependent upon the rate of ubiquinol oxidation by the iron-sulfur protein.

168 vely reproduces key features observed during ubiquinol oxidation by the mitochondrial cytochrome bc1

169 n alternating half-of-the-sites mechanism of ubiquinol oxidation in the bc(1) complex dimer.

170 Together these results indicate that ubiquinol oxidation is a concerted reaction in which bot

171 evidence for the early involvement of ISP in ubiquinol oxidation is not available.

172 esults indicate that atovaquone binds to the ubiquinol oxidation pocket of the bc1 complex, where it

173 lurins which inhibit the same complex at the ubiquinol oxidation site (Q(o) site).

174 en together, these results indicate that the ubiquinol oxidation site at center P is damaged in the b

175 get organisms by specifically binding to the ubiquinol oxidation site at center P of the cytochrome b

176 ing the kinetics of inhibitor binding to the ubiquinol oxidation site at center P.

177 The maximal capacity of the ubiquinol oxidation site in complex III in generating RO

178 Because these inhibitors bind to the ubiquinol oxidation site in the bc(1) complex, we propos

179 One of these binding sites, the ubiquinol oxidation site, is clearly in dynamic equilibr

180 of superoxide production in Complex III, the ubiquinol oxidation site, is situated immediately next t

181 conditions that allow the first turnover of ubiquinol oxidation to be observable in cytochrome c(1)

182 To understand better the mechanism of ubiquinol oxidation, we have examined the interaction of

183 least an order of magnitude than the rate of ubiquinol oxidation.

184 effectively to menaquinol oxidation than to ubiquinol oxidation.

185 binds analogous to reaction intermediates of ubiquinol oxidation.

186 ns in RTN4IP1, which encodes a mitochondrial ubiquinol oxydo-reductase.

187 ome, salicylhydroxamic acid (SHAM)-sensitive ubiquinol:oxygen oxidoreductase known as trypanosome alt

188 In contrast, QH*- serves to oxidize a ubiquinol pool in the course of electron transfer from t

189 a single, universally accessible ubiquinone/ubiquinol pool that is not partitioned or channeled.

190 in the course of electron transfer from the ubiquinol pool to the oxygen-consuming center of termina

191 action centers whose function is to reduce a ubiquinol pool.

192 re, we focus on the mitochondrial ubiquinone/ubiquinol pool.

193 Much evidence suggests that ubiquinol (QH2) functions as an effective antioxidant in

194 tion, as further increases in [NADH] elevate ubiquinol-related complex III reduction beyond the optim

195 itions modified to account for the fact that ubiquinol reoxidation is limited by enzyme activity.

196 itions modified to account for the fact that ubiquinol reoxidation is limited by enzyme activity.

197 traightforward entries to polyethyleneglycol ubiquinol succinate (PQS, n = 2), a designer surfactant

198 te reductase A couples more effectively with ubiquinol than with menaquinol.

199 e bo(3) has a high affinity binding site for ubiquinol that stabilizes a ubi-semiquinone.

200 ermore, when the oxidized enzyme reacts with ubiquinol (the reduced form of the usual electron accept

201 he Rieske iron-sulfur cluster cannot oxidize ubiquinol through center P, rates of reduction of cytoch

202 tochrome b but has no effect on oxidation of ubiquinol through center P.

203 lex catalyzes the transfer of electrons from ubiquinol to cyt c while generating a proton motive forc

204 s that might be important for the binding of ubiquinol to cytochrome bo3.

205 rsion during the transport of electrons from ubiquinol to cytochrome c (or alternate physiological ac

206 They catalyze electron transfer (ET) from ubiquinol to cytochrome c and concomitantly translocate

207 Cytochrome bc1 transfers electrons from ubiquinol to cytochrome c and uses the energy thus relea

208 ric enzyme that links electron transfer from ubiquinol to cytochrome c by a protonmotive Q cycle mech

209 ble for the transfer reducing potential from ubiquinol to cytochrome c coupled to the movement of cha

210 It funnels electrons coming from NADH and ubiquinol to cytochrome c, but it is also capable of pro

211 of mitochondria and transfers electrons from ubiquinol to cytochrome c.

212 s required to mediate electron transfer from ubiquinol to cytochrome c1.

213 component in order to shuttle electrons from ubiquinol to cytochrome c1.

214 s by one half and causes the apparent Km for ubiquinol to decrease from 9.3 to 2.6 microM.

215 rotein (ISP) accepts the first electron from ubiquinol to generate ubisemiquinone anion to reduce b(L

216 the transfer of electrons from the substrate ubiquinol to heme b.

217 Electron transfer from ubiquinol to NapAB was totally dependent upon NapGH, but

218 pF, are essential for electron transfer from ubiquinol to NapAB.

219 a Q cycle, as electrons are transferred from ubiquinol to NapC.

220 diiron protein that transfers electrons from ubiquinol to oxygen, reducing the oxygen to water.

221 reverse reaction, Deltap-linked oxidation of ubiquinol to reduce NAD(+) (or O(2)), known as reverse e

222 echanism of divergent electron transfer from ubiquinol to the iron-sulfur protein and cytochrome b(L)

223 inly involved in transferring electrons from ubiquinol to the oxidase.

224 the bc(1) complex is electron transfer from ubiquinol to the Rieske iron-sulfur protein (ISP) at the

225 ative oxidase (AOX)(12), which also oxidizes ubiquinol to ubiquinone.

226 coenzyme Q(10), CoQ(10)): the reduced form, ubiquinol, traps lipid peroxyl radicals that mediate lip

227 characterize the diffusion properties of the ubiquinol/ubiquinone in the tethered membrane system.

228 characterize the diffusion properties of the ubiquinol/ubiquinone in the tethered membrane system.

229 the redox potentials of the NADH/NAD(+) and ubiquinol/ubiquinone pools.

230 least one and possibly two binding sites for ubiquinol/ubiquinone.

231 In hypoxia, ubiquinol (UQH(2)) diverts these electrons onto fumarate

232 enter), the enzyme is primed to reduce UQ to ubiquinol via FAD.

233 tochrome b reduction by either menaquinol or ubiquinol was rapid and monophasic.

234 '-tetramethyl-p-phenylenediamine in place of ubiquinol was, however, unimpaired by the mutations, ind

235 s G3P oxidation with ubiquinone reduction to ubiquinol, which acts as a radical-trapping antioxidant

236 y for rapid electron transfer from substrate ubiquinol, which binds at a separate site (QL), to heme

237 at tumour growth requires the ETC to oxidize ubiquinol, which is essential to drive the oxidative TCA

238 linker region is critical for interaction of ubiquinol with the bc1 complex, consistent with electron

239 interaction of several inhibitory analogs of ubiquinol with the yeast cytochrome bc(1) complex.