ライフサイエンスコーパス: proton donor

1 which is positioned to serve as the initial proton donor.

2 can reduce N(2) in the presence of PhOH as a proton donor.

3 m stabilization by solvent water acting as a proton donor.

4 postulated to adopt the role of active site proton donor.

5 that requires significant desolvation of the proton donor.

6 sm where H2O, in addition to H+, serves as a proton donor.

7 gy to an extent dependent on the strength of proton donor.

8 consistent with water being the active site proton donor.

9 -298 is correctly located to function as the proton donor.

10 or a conserved acidic residue that acts as a proton donor.

11 donor employed, and the concentration of the proton donor.

12 quantum calculations show it to be a potent proton donor.

13 ses it was beneficial to add an alcohol as a proton donor.

14 at D210 likely operates as the leaving group proton donor.

15 a proton acceptor and, subsequently, Asp96 a proton donor.

16 bstrate and that R67 DHFR does not possess a proton donor.

17 shed and this residue thereby becomes a good proton donor.

18 e Hunig base as the sacrificial electron and proton donor.

19 itic growth was observed in the absence of a proton donor.

20 r NO or NH(4)(+) in the presence of a modest proton donor.

21 active-site histidine serving as the second proton donor.

22 dard potential as dictated by the pKa of the proton donor.

23 ng into account the presence of an exogenous proton donor.

24 activation by acting as both an electron and proton donor.

25 d proton transfer, and the role of Tyr196 as proton donor.

26 posed to serve as a transiently deprotonated proton donor.

27 ing group, with a neutral Asp132 as a likely proton donor.

28 erring H(+) is initially associated with the proton donor.

29 Co(III)-hydride is formed by reaction with a proton donor.

30 ta2-N2) was also accomplished by addition of proton donors.

31 that were previously identified as possible proton donors.

32 cene and weak O-H bonds upon activation with proton donors.

33 potential and in the absence of electrolyte proton donors.

34 mer Bronsted bases blended with organic acid proton donors.

35 H-bonding stabilizers and high-concentration proton donors.

36 However, in the absence of a proton donor a strong Fe-F bond can be obtained as shown

37 he catalytic pathway from the pai-associated proton donor, a system was assessed that produced measur

38 vibronic coupling and its dependence on the proton donor-acceptor distance can significantly impact

39 ic coupling decreases exponentially with the proton donor-acceptor distance for the range of distance

40 To test the effect of varying the proton donor-acceptor distance in proton-coupled electro

41 r as the proton acceptor in part because the proton donor-acceptor distance is approximately 0.2 A sm

42 In this empirical model, the proton donor-acceptor distance is predicted to be larges

43 This dominant proton donor-acceptor distance is significantly smaller

44 ster than the first reaction since a smaller proton donor-acceptor distance leads to a larger overlap

45 del is not a good predictor of the effect of proton donor-acceptor distance on concerted-electron tra

46 strong dependence of proton transfer on the proton donor-acceptor distance provides an explanation f

47 alf arise from the change in the equilibrium proton donor-acceptor distance upon electron transfer.

48 compression; however, the relevant C...O(-) proton donor-acceptor distance was longer, due to a twis

49 isotope effect is strongly influenced by the proton donor-acceptor distance with the dominant contrib

50 ent-coupled dynamic networks to optimize the proton donor-acceptor distance, but evolutionary pressur

51 e carboxylate also decreases the equilibrium proton donor-acceptor distance, thereby facilitating the

52 rather than from compression of the C...O(-) proton donor-acceptor distance.

53 The decrease in proton donor-acceptor distances due to thermal fluctuati

54 e in a manner that decreases the equilibrium proton donor-acceptor distances or alters the molecular

55 y designing systems with shorter equilibrium proton donor-acceptor distances.

56 thereby facilitating the sampling of shorter proton donor-acceptor distances.

57 kinetic isotope effect increases for larger proton donor-acceptor distances.

58 vibrational wave function overlap for larger proton donor-acceptor distances.

59 ation was shown to be facilitated by shorter proton donor-acceptor distances.

60 f the KIE is determined predominantly by the proton donor-acceptor frequency and the distance depende

61 e overall rate is strongly influenced by the proton donor-acceptor frequency, the vibronic coupling,

62 relation functions of the energy gap and the proton donor-acceptor mode, which can be calculated from

63 ited electron-proton vibronic states and the proton donor-acceptor motion provided an apparent reorga

64 bond, which corresponds to a high-frequency proton donor-acceptor motion, and small inner-sphere and

65 n, as well as the solvent reorganization and proton donor-acceptor motion.

66 s and is not significantly influenced by the proton donor-acceptor motion.

67 the dominance of the local component of the proton donor-acceptor motion.

68 functions and the incorporation of multiple proton donor-acceptor motions.

69 eplacements, these substitutions perturb the proton donor-acceptor relative orientation change and th

70 cal and quantum mechanical treatments of the proton donor-acceptor vibrational motion are presented.

71 Thus, the proton donor-acceptor vibrational motion plays a vital r

72 sists of an aspartate residue serving as key proton donor/acceptor (Asp-684) and an arginine residue

73 ding to mutagenesis experiments, the role of proton donor/acceptor along the D-pathway is carried by

74 e pathway, in close proximity to the central proton donor/acceptor Asp-684.

75 atalytic role in both partial reactions as a proton donor/acceptor at the 3'-OH/3'-keto center.

76 y, site accessibility, and the presence of a proton donor/acceptor group near the reaction site, are

77 Activation by 4-MI as proton donor/acceptor in catalysis was determined in the

78 entation may play in its ability to act as a proton donor/acceptor in HCA II.

79 Histidine-86 has emerged as a potential proton donor/acceptor in the catalytic mechanism based o

80 These results directly establish E17 as a proton donor/acceptor in the Nia-S <--> Nia-C equilibriu

81 is simple mononuclear system illustrates how proton donor/acceptor ligands can vastly increase the ra

82 ding sites that include the proposed initial proton donor/acceptor of the K pathway, Glu-101 of subun

83 and the fully reduced FAD, functioning as a proton donor/acceptor to FAD.

84 between the redox center and phosphate as a proton donor/acceptor.

85 nitiated by Lys 52 or Lys 410 as the primary proton donor/acceptor.

86 s for imidazole and derivatives as exogenous proton donors/acceptors in catalysis by HCA III.

87 rovide their carboxylic groups as substitute proton donors/acceptors in the absence of Glu-101II, as

88 la (H64A HCA II) can be rescued by exogenous proton donors/acceptors, usually derivatives of imidazol

89 The relationship between proton-donor affinity for Sm(II) ions and the reduction

90 mplements neither substrate modification nor proton donor agents in the aqueous solution, known to fa

91 osine can fulfill the role of an active site proton donor, albeit very poorly.

92 the desirable Pd(II)-precatalyst, (b) a soft proton donor and a bidentately coordinated dianionic lig

93 gen-bonding interactions and by bringing the proton donor and acceptor closer to each other with the

94 arge around the frontier atoms than when the proton donor and acceptor groups are alternating as in D

95 ed a role for phosphoric acid and acetate as proton donor and acceptor in the concerted electron-prot

96 ulated as a function of the distance between proton donor and acceptor nitrogen atoms.

97 Compression of the distance between the proton donor and acceptor oxygen atoms of the interfacia

98 intrinsically slow proton exchange between a proton donor and acceptor pair that are not in close con

99 h a hydrogen-bond relay inserted between the proton donor and acceptor sites was studied electrochemi

100 The electrolyte consists of a proton donor and acceptor slurry containing substituted

101 hich apparently hinder the close approach of proton donor and acceptor that facilitates MS-CPET.

102 evealed that resveratrol functions as both a proton donor and acceptor, contributing to its strong ta

103 y a unique His residue that acts as both the proton donor and acceptor.

104 ns in the catalytic cycle, namely first as a proton donor and later as the substrate in the reaction

105 idic side chains that could serve as general proton donor and nucleophile/base in a canonical hydroly

106 attraction between the dipole moments of the proton donor and proton acceptor must be balanced by the

107 The asymmetry in angular rigidity of the proton donor and proton acceptor of hydrogen-bonded hydr

108 nzoate or p-aminobenzoate, reveal a chain of proton donors and acceptors (the hydroxyl groups of Tyr2

109 h comprise active hydrogen atoms that act as proton donors and acceptors, simultaneously hindering em

110 and deprotonated forms, as well as different proton donors and acceptors.

111 f CO2(*-), which can dimerize and react with proton donors and even mild oxidants.

112 t with the shifts observed in other H-bonded proton donors and provides corroborating spectral eviden

113 Transfer of water between the chain of proton donors and the solvent also appears to be an esse

114 the NH amide proton of the upper side chain (proton donor) and glycine acetamide of the lower side ch

115 H(3)(+) is a strong acid (proton donor) and initiates chains of ion-molecule react

116 d Glu359 may function as the catalytic acid (proton donor) and nucleophile (base), respectively, duri

117 hange in distance between the phenol oxygen (proton donor) and quinoline nitrogen (proton acceptor),

118 u(I) :1S redox state, use of a second-sphere proton donor, and reactivity dependence on both primary

119 In the absence of a proton donor (as occurs in H84N), the normal reaction pa

120 wering the pKa of asp-96, so as to make it a proton donor, as the third phase.

121 n acceptor rather than being the anticipated proton donor, as would be expected if Asp beta99 were io

122 plex, the protonation states of the electron/proton donor (ascorbate) and all of the residues involve

123 dopsin photocycle is greatly slowed when the proton donor Asp-96 is removed with site-specific mutage

124 ules located between the Schiff base and the proton donor Asp96 in the cytoplasmic region.

125 tending from the Schiff base to the internal proton donor Asp96, stabilizes L and affects the L-to-M

126 llus stearothermophilus, considered possible proton donors at the active site, was carried out.

127 ton transfer into the RC, acting as RC-bound proton donors at the entrance of the proton-transfer pat

128 nvolving nitrogen, sulfur, and phosphorus as proton-donor atoms.

129 Lysine 230 was suggested to act as proton donor based on geometry and spatial proximity to

130 center or the absence of a lone pair on the proton donor, because F(3)Si-H.OH(2), F(2)NH.FH, F(2)PH.

131 ates through protonation implicating another proton donor besides E241.

132 47 or Lys48, functions as a rate-determining proton donor between pH 6 and pH 8.

133 Proton donors bound at the less flexible side chain of T

134 -O bond in 2 in the presence of electron and proton donors by a proton-coupled electron-transfer (PCE

135 The pigment lacks the proton donor carboxylate residue in helix C conserved in

136 anced monomer stability, lowering the pKa of proton donor catalytic residue, optimized spatial distri

137 hancement of catalytic activity by exogenous proton donors containing imidazole rings.

138 d ribonuclease cleavage mechanisms where the proton donor coordinates with the oxygen of the leaving

139 events rapid back-transfer by increasing the proton-donor coordination.

140 High-affinity proton donor cosolvents such as water and glycols also d

141 is of a judicious choice of a Sm(II) complex/proton donor couple, even in the presence of extremely s

142 Our results reveal that when the proton donors D (which are electron-donating) and the pr

143 circumvents a requirement for expulsion by a proton donor during attack by cysteine on the gamma phos

144 served Tyr that is proposed to function as a proton donor during reductive dehalogenation.

145 y been proposed to play a critical role as a proton donor during the second half-reaction of MurB, na

146 a key role of second-sphere N-H residues as proton donors during N(2) O reduction.

147 loproteins distribute added charge and poise proton donors during reactions with dioxygen.

148 These results suggest that there are two proton donors during the activation of UV pigments, the

149 hat 2-e reduced forms develop H-bonding with proton donors (e.g., CH3OH) via the O-atom.

150 chiff base through a mutation of the primary proton donor (E108Q).

151 acid-base chemistry, we mutated the putative proton donor E17 to Q in the soluble hydrogenase I from

152 idues (H21G, E24D/G, and H116G), the general proton donor (E178A), and mutants designed to switch the

153 The proton donor E42 is placed in the helix B.

154 figuration of the diastereomer reacting, the proton donor employed, and the concentration of the prot

155 In K240M, the proton donor exchanges protons with the solvent at a hig

156 the 64 complexes in which these monomers are proton donors exhibit significant scatter.

157 d a glutamate at position 132 that acts as a proton donor for chromophore reprotonation during the ph

158 ning alcohol products by serving as a strong proton donor for electrochemical dehydration reductions.

159 n in the active site, cannot function as the proton donor for fumarate reduction.

160 e catalytic site and implicating His241 as a proton donor for leaving group activation.

161 ment Tyr 34 --> Phe suggest that Tyr 34 is a proton donor for O2* - reduction to H2O2 or is involved

162 e/bicarbonate exchanger), where it acts as a proton donor for the anion/proton cotransport function.

163 t a beta-hydroxylmethyl side chain acts as a proton donor for the binding of a novel ligand.

164 Glu(131) is a likely proton donor for the hydroxyl leaving group.

165 ore, we conclude that Glu46 functions as the proton donor for the protonation of pCA during the PYP p

166 Rather, H2O serves directly as the proton donor for the reaction.

167 otonated in pG and protonated in pB, but the proton donor for this process has not yet been identifie

168 r catalysis and may function indirectly as a proton donor for turnover, coupled to a protonation cycl

169 As one of the primary proton donors for CO(2) reduction, H(2)O is essential to

170 ed to twist into a conformation blocking the proton donor from its side, thus reversing the stereoche

171 However, bimolecular protonation by a proton donor from the bulk may be too slow to compete wi

172 omplished by separating the initial phenolic proton donor from the pyridine-based terminal proton acc

173 ed by general acid/base (proton acceptor and proton donor) functionality, with nucleophilic addition

174 action, protonation of the substrate, by the proton donor glutamate.

175 However, the proton donor, glutamate 139 is also unexpectedly a membe

176 re attempted by the placement of a potential proton donor group at the active site.

177 een performed to decipher the influence of a proton-donor group on O-O bond activation.

178 However, molecules with strong proton donor groups, in particular, are tenaciously reta

179 s that hydrogen bonds from hydroxyl or other proton-donor groups to carbonyl oxygens potentially can

180 Chiral Bronsted acids (proton donors) have been shown to facilitate a broad ran

181 chain of hydrogen-bonded waters linking the proton donor His64 and acceptor zinc-bound hydroxide.

182 s64, yet the difference in p K a between the proton donor His64 and zinc-bound hydroxide was near zer

183 ifferences in the values of the pK(a) of the proton donor (His64) and acceptor (zinc-bound hydroxide)

184 esence of iron(II) shows a requirement for a proton donor, implying a role for an acidic group in the

185 he shift expected for tryptophan acting as a proton donor in a T-state hydrogen bond.

186 g evidence that Y171 does not operate as the proton donor in catalysis and that the additional role o

187 mutants indicate that Tyr425' is the primary proton donor in catalysis, with Tyr367' functioning as a

188 nd does not support the role of Asp 258 as a proton donor in catalysis.

189 implying that the catalytic Lys may act as a proton donor in catalysis.

190 critical role of the solvent environment and proton donor in dictating the mechanistic landscape of C

191 he assignment of an arginine (Arg402) as the proton donor in fumarate reduction.

192 another aspartic acid residue functions as a proton donor in hydrolysis.

193 ition of exogenous imidazole which acts as a proton donor in place of the imidazole groups of His tha

194 ate that transiently protonated Lys47 is the proton donor in tetrahedral intermediate collapse to the

195 ce 2-enoyl-CoA, whereas Glu164 serves as the proton donor in the absence of Tyr166 to yield 3-enoyl-C

196 ncerted with proton transfer from an unknown proton donor in the active site.

197 xyl of Tyr34 is hydrogen bonded, acting as a proton donor in the active site.

198 acceptor in the hydration direction and the proton donor in the dehydration direction for the rate-l

199 pH and, therefore, is capable of acting as a proton donor in the enzyme-catalyzed reaction.

200 r studies suggested histidine as a potential proton donor in the hydrolysis of sucrose, but by mutage

201 rfaces and highlight the crucial role of the proton donor in the kinetics of electrocatalytic energy

202 oxylase activity and that Glu333 serves as a proton donor in the production of formate.

203 te that Y158 does not function formally as a proton donor in the reaction but likely functions as an

204 OD for DHO deuterated at the 5-position (the proton donor in the reaction).

205 catalytic residue, probably functioning as a proton donor in the reductive acylation of lipoamide on

206 Glu164 seems to function as proton donor in the Tyr166Phe mutant, because the Tyr166

207 r166 with the assistance of His252 acting as proton donor in the wild-type enzyme to produce 2-enoyl-

208 t an essential role of Glu202 as the initial proton donor in this isomerization reaction.

209 vor the epsilon-amino group of Lys166 as the proton donor in this step.

210 gher rate relative to turnover than does the proton donor in wild-type YPK.

211 s to the class of high-acidity excited-state proton donors in photochemistry and photobiology.

212 s to the class of high-acidity excited-state proton donors in photochemistry and photobiology.

213 equivalent efficiency of Glu64 and Asp64 as proton donors in the catalysis by CA III demonstrate a l

214 with the proposed roles of these residues as proton donors in the first step of catalysis.

215 are best to be avoided; (ii) the addition of proton donors in the form of protonated weak bases can b

216 ed by 4-methylimidazole (4-MI), an exogenous proton donor, in a saturable process with a maximum acti

217 First, ESR's proton donor is a lysine side chain that is situated ver

218 However, its role as a proton donor is still debated.

219 termolecular bending frequency of HF, as the proton donor, is linearly proportional to the square roo

220 This -SH group serves as a proton donor, is responsible for the biological activity

221 and in the case of a ligand, which is also a proton donor, it may also enhance the reaction by proton

222 midazole groups of the His-H126 and His-H128 proton donors, located at the entrance of the transfer p

223 The mechanistic importance of HMPA and proton donors (methanol, 2-methyl-2-propanol, and 2,2,2-

224 alysis, which suggested that the presence of proton donors might further enhance rates.

225 This accumulation of charge makes the proton donors more positive and the proton acceptors mor

226 If Lys166 indeed serves as the terminal proton donor, mutants lacking an ionizable side chain at

227 ow show that when alpha-195(His), a putative proton donor near the active site, is substituted by glu

228 Tr complex (revealed here) lacks any obvious proton donor near the N5 group.

229 as postulated that residue Cys-82 may be the proton donor of the decarboxylation reaction catalyzed b

230 that a proton-relay system is acting as the proton donor of the reaction (1).

231 on of CO(2) hydration at steady state and as proton donors of the exchange of (18)O between CO(2) and

232 of nonproductive binding sites for exogenous proton donors offers an explanation for the unusually lo

233 The effect of the proton donor on the kinetics of interfacial concerted pr

234 e of commonly added, supposedly sacrificial, proton donors on SEI chemistry and morphology remains a

235 gesting the importance of lysine as either a proton donor or a stabilizing cation during strand cleav

236 lysis with a cytosine side chain acting as a proton donor or acceptor.

237 talytic response with a strong dependence on proton donor p K(a).

238 Instead, it acts as a viable proton donor past the rate-limiting step and a sluggish

239 on of a vibrational Stark-shift probe with a proton donor provides critical insight into the interpla

240 of the excited state molecule occurs when a proton donor reacts with the carboxylate during the exci

241 cid strength and the presence of the pendent proton donor relay.

242 d MR, suggesting that His-186 is not the key proton donor required for the reduction of 2-cyclohexen-

243 be inactive due to the loss of its putative proton donor residue, exhibited 27% of the wild-type act

244 Here, we mutagenized the predicted proton donor residues and the nucleophilic catalyst resi

245 rmed the catalytic function of the predicted proton donor residues, and sequence analysis suggested t

246 t Asp-97 and Glu-108 are proton acceptor and proton donor, respectively, in retinylidene Schiff base

247 ch boosted the paralleled catalytic surge of proton donors, resulting in an attomolar detection limit

248 l chloride in concert with a noncoordinating proton donor source.

249 These results demonstrate that proton donor structure strongly impacts the free energy

250 or even more efficient than widely employed proton donors such as ureas or dicarboxamides.

251 ue such as HisH(+) makes for a very powerful proton donor, such that even its CH..O H-bonds are stron

252 Acid-base reactions involving cyanide and proton donors, such as amino acids and other cell cultur

253 on structures and peptide domains, including proton donors, suggest that MGA and SI evolved by duplic

254 Here, we have combined a proton donor (tertiary ammonium) with a vibrational Star

255 Trihydrogen-phosphate is a much better proton donor than dihydrogen- and monohydrogen-phosphate

256 A proton donor that complexes efficiently with SmI(2) must

257 al, and kinetic studies show that only those proton donors that coordinate or chelate strongly to Sm(

258 In the presence of strong proton donors the electrochemistry of the quinone become

259 In response to chemical substitutions of the proton donor, the energy of the transition state for dir

260 he proton acceptor Asp85 is connected to the proton donor, the retinal Schiff base, through a hydroge

261 By using strong (acidic) proton donors, the formal potential of the quinone redox

262 chanistic investigations suggest a switch of proton donor to account for the stereoinvertive formatio

263 his pKa is likely to be that of the internal proton donor to Asp-194, the Glu-204 site, before photoe

264 er molecule in a water channel is the direct proton donor to enolpyruvate and that Thr-298 affects a

265 pH, affecting the protonation state of D396 (proton donor to FAD degrees (-)).

266 the pKa of aspartic acid D396, the putative proton donor to FAD.(-), from ~7.4 to >9, and favours a

267 led that, in addition to its function as the proton donor to fructose-6-phosphate during formation of

268 His(85) is a potential proton donor to reactive iron-oxo species during substra

269 The nature of the proton donor to the C-3 of the enolate of pyruvate, the

270 om the second monomer, is postulated to be 2 proton donor to the carbanion intermediate.

271 oton transfer from the His215 catalytic site proton donor to the deoxyadenosine 5'-oxygen in the tran

272 d that serine 229 was positioned to act as a proton donor to the developing C2 carbanion during the r

273 is that involves rate-limiting CPET from the proton donor to the electrode surface, allowing this cat

274 uestions on the role water plays as a direct proton donor to the iron-linked dioxygen.

275 y a hydroxide ion with H125 functioning as a proton donor to the leaving alcohol group.

276 ates that very unusually the N3 of A1 is the proton donor to the oxyanion leaving group.

277 The proposed role of H84 is as a proton donor to the oxyanion of the quinoid species such

278 with the presence of a hydrogen bond from a proton donor to the phenolic oxygen atom of a neutral ty

279 as OH..phi bonds formed by the approach of a proton donor to the pi electron cloud above the aromatic

280 l carboxyl group is in place of the internal proton donor to the retinal Schiff base in the light-dri

281 which substantiates its role as the internal proton donor to the retinal Schiff base.

282 on donors for reducing the catalyst and (ii) proton donors to activate the substrate via a proton-cou

283 h could lead to different accessibilities of proton donors to the binuclear center.

284 he Tyr and a conserved Asp are implicated as proton donors to the epoxide leaving group.

285 of glutamic acid 64 and aspartic acid 64 as proton donors to the zinc-bound hydroxide in a series of

286 oton acceptor (typically an enolate) and the proton donor (typically a thiol).

287 en-bonding interactions with the acetic acid proton donor upon reduction from Fe(III)/(II), favoring

288 that the activation of H64W HCA II by these proton donors was reflected in the work functions w(r) a

289 In the presence of HMPA, the rate order of proton donors was zero and product studies showed that t

290 ed in a position to serve potentially as the proton donor, was mutated to cysteine.

291 henolate hydrogen bond and that Tyr16 is the proton donor when a bound naphtholate inhibitor is obser

292 lar protonation could be achieved by using a proton donor which complexes to SmI2, in which case the

293 e of the active site cavity, is the proposed proton donor which facilitates purine base departure.

294 ly degradation, limiting the strength of the proton donor which may be used.

295 es from an unfavorable preassociation of the proton donor with the superoxide adduct and a transition

296 dazole and pyridine derivatives as exogenous proton donors with the indole ring of Trp-64; these expe

297 ding the conserved catalytic nucleophile and proton donor, with endoglucanases from glucosyl hydrolas

298 otentials, solvent water becomes the primary proton donor, with multiple competing mechanisms observe

299 Radical anions are well known to react with proton donors, yet their reactivity with hydrides remain

300 p by NADH, assisted by Tyr(147) as catalytic proton donor, yields UDP-xylose adopting the relaxed (4)