ライフサイエンスコーパス: proton transfer

1 s trans-to-cis chromophore isomerization and proton transfer.

2 oton-uncoupled pathway that does not involve proton transfer.

3 hway are catalyzing reaction steps involving proton transfer.

4 ves a very low activation energy pathway for proton transfer.

5 dered amine shifts the rate-limiting step to proton transfer.

6 termediates that differ by an intramolecular proton transfer.

7 ot present in controls that are incapable of proton transfer.

8 drogen bond and the phosphate anion promotes proton transfer.

9 8-DEA-tC against quenching by excited state proton transfer.

10 argely expressed at the transition state for proton transfer.

11 nding to the initial stage of intermolecular proton transfer.

12 more facile for configurations conducive to proton transfer.

13 reversible kinetic responses associated with proton transfer.

14 ire independent control of both electron and proton transfer.

15 e effected, indicating kinetic inhibition of proton transfer.

16 sis and a membrane-embedded V(o) complex for proton transfer.

17 a hangman effect derived from intermolecular proton transfer.

18 t serves to bind CO(2) and also to assist in proton transfer.

19 zeolite pore walls from those of pore-phase proton transfer.

20 pumps, which serves as a bridge for the key proton transfer.

21 ially serves as a pH-dependent regulator for proton transfer.

22 alcohol reagent, takes part in assisting the proton transfer.

23 ioning involves chemical reactions including proton transfer.

24 nit and the phenolic OH generated during the proton transfer.

25 he solvent identity plays a dominant role in proton-transfer.

26 -N bond ruptures, hydroxide attachments, and proton transfers.

27 hydrogen bonding (1), NH-insertion (2,3), or proton transfer (4) products can be isolated, each displ

28 ituent on the Criegee carbon that lowers the proton transfer ability and inhibits the formation of a

29 Electron transfer induced proton transfer across a H-bond can be used to significa

30 luorescent protein fibrils are permissive to proton transfer across hydrogen bonds which can lower el

31 al of DDD-AAA H-bond dimers, consistent with proton transfer across the central H-bond upon reduction

32 central carbon of silyl ketene, followed by proton transfer afforded alpha-silyl ester, amide, or th

33 d hydride transfer from NADPH and long-range proton transfer along structurally defined proton-transf

34 hael addition-6pi-electrocyclic ring opening-proton transfer and 6pi electrocyclization, in which a v

35 y invoked mechanism of concerted amine/thiol proton transfer and C-S bond formation and instead sugge

36 Phenols and quinols participate in both proton transfer and electron transfer processes in natur

37 Reactions that involve a combination of proton transfer and heavy-atom bonding changes are norma

38 In addition to significant changes in amide proton transfer and semisolid macromolecular magnetizati

39 n of which to Glu produced early Schiff base proton transfer and strongly inhibited channel activity.

40 nium ions in aqueous solutions is related to proton transfer and structural diffusion.

41 histidine, allow for studies of the role of proton transfer and tautomeric state in enzymatic mechan

42 The results of photoinduced proton transfer and voltage-driven proton-conductivity m

43 formation, promote mechanistically important proton transfers and stabilize multiple transition state

44 involving reprotonation, intramolecular 1,6 proton transfer, and concerted but asynchronous bicycliz

45 While proton transfer appears to be impaired in the oxidized s

46 Amide proton transfer (APT) imaging is a noninvasive molecular

47 conclude that solvent-iron dissociation and proton transfer are both associated with the CCD catalyt

48 ional studies indicate that this barrier for proton transfer arises from an unfavorable preassociatio

49 The quenching occurs via electron/proton transfer, as evidenced by transient absorption sp

50 ation transfer asymmetry (MTRasym) and amide proton transfer asymmetry (APTasym) are presented.

51 lecular dynamic simulations, we screened the proton transfer barrier for different un-doped and nitro

52 idges initiates loss of the ligand, but that proton transfer becomes energetically unfavorable in the

53 ectrocatalytic reversibility as electron and proton transfers begin to be decoupled.

54 and thermal noise leads to efficient uphill proton transfer, being a manifestation of stochastic res

55 initiate polymerization and facilitate rapid proton transfer between active and dormant chains.

56 wo protons before and after a pH-induced two-proton transfer between catalytic aspartic acid residues

57 The reaction involves a direct proton transfer between HMSA and (R1)(R2)NH, and the res

58 polar-cleavage mechanism (electron transfer-proton transfer) by the iron(III)-hydroxo, as opposed to

59 we show the intramolecular electron-induced proton transfer capability of a long list of molecules t

60 ate for these processes contains significant proton transfer character.

61 ed on ion-ion proton transfer, herein termed proton transfer charge reduction (PTCR), to investigate

62 evels and mutual interactions among electron/proton transfer components and their associated light-ha

63 nging the driving force for the electron and proton transfer components of the reaction through varyi

64 Intramolecular electron-induced proton transfer could have potential applications such a

65 Electron-induced proton transfer depicts the proton motion coupled with t

66 epends predominantly on the oxidant, and the proton transfer driving force depends mainly on the basi

67 Ser(130), it is suggested to play a role in proton transfer during catalysis of the antibiotics.

68 site tRNA that is required for the efficient proton transfer during peptide bond formation.

69 nd investigated the kinetics of electron and proton transfer during the reaction of the reduced CytcO

70 ion pairs and charged residues modulate the proton transfer dynamics, and how transmembrane helices

71 reas the 1,4-dinitrobenzene did not show any proton transfer effect in the experimental conditions em

72 aromatic in the first (1)paipai* states, and proton transfer (either inter- or intramolecularly) help

73 s using refined coupled (PCET) and decoupled proton transfer-electron transfer (PT/ET) schemes involv

74 change in mechanism across the series, from proton transfer/electron transfer for X = NO(2), CF(3),

75 R occurs through a general electron transfer/proton transfer/electron transfer/proton transfer pathwa

76 These results do not support a discrete proton-transfer/electron-transfer process, but rather an

77 lifetime dynamics expected for excited-state proton-transfer emitters.

78 including predicting isomerization energies, proton transfer energies, and highest occupied molecular

79 addition to increasing the driving force for proton transfer, enhancing the basicity of the carboxyla

80 that undergoes excited-state intramolecular proton transfer (ESIPT) in neat CH3CN where photodeamina

81 ate through the excited-state intramolecular proton transfer (ESIPT) photochemical process.

82 atives using an excited-state intramolecular proton transfer (ESIPT) process.

83 e sensing to be excited-state intramolecular proton transfer (ESIPT).

84 ples (including excited-state intramolecular proton transfers (ESIPT), biprotonic transfers, dynamic

85 Selective excited-state intramolecular proton-transfer (ESIPT) photocycloaddition of 3-hydroxyf

86 When irradiated with light, excited-state proton transfer (ESPT) occurs from cationic side-chains

87 kes shift is tightly linked to excited-state proton transfer (ESPT) of the protonated chromophore, we

88 d's rule explains why and when excited-state proton transfer (ESPT) reactions happen in organic compo

89 luorescence is quenched due to excited-state proton transfer (ESPT) to solvent.

90 making of covalent bonds, and excited-state proton transfer (ESPT).

91 undergo a relay type of excited-state triple proton transfer (ESTPT) in a concerted, asynchronous man

92 a key factor that regulates the branching of proton transfer events and therefore contributes to the

93 ether with the interplay of the electron and proton transfer events during the aromatic ring reductio

94 and FTIR spectroscopy, we characterized the proton transfer events in the photocycle of ReaChR and d

95 he membrane, for following fast (nanosecond) proton transfer events on the surface of membranes.

96 oposed catalytic mechanism requires multiple proton-transfer events.

97 Ligand derived proton transfer facilitates N-O bond cleavage of a putat

98 and reveal the consequences of slowing down proton transfer for both catalytic directions over a wid

99 sotope effects support concerted hydride and proton transfer for both light and heavy LDHs.

100 ransfer from the nickel to the porphyrin and proton transfer from a carboxylic acid hanging group or

101 To the best of our knowledge, utilization of proton transfer from a conventional photoacid for the op

102 The proton relay mechanism postulates proton transfer from a highly conserved histidine centra

103 In the lowest energy pathway, proton transfer from Hantzsch ester, a weak Bronsted aci

104 addition, with a higher rate than the direct proton transfer from hydronium ions.

105 the existence of a possible pathway by which proton transfer from Lys 73 to Ser 130 can occur.

106 methylammonium lead bromide, which induces a proton transfer from methylammonium to benzylamine and e

107 C-O bond cleavage step, with an intermediate proton transfer from nitrogen to oxygen facilitated by a

108 on of an ion pair created by shock-triggered proton transfer from phenol to PVP.

109 We show that proton transfer from protonated ligand to deprotonated R

110 nd scission is very low and that synchronous proton transfer from the 2'-hydroxyl to the departing ph

111 irst step in a catalytic cycle that requires proton transfer from the bulk at the N-side to the BNC.

112 pports the hypothesis that the photo-induced proton transfer from the chromophore occurs through wate

113 ron-rich enolate or through coupled electron-proton transfer from the enol, in any case generating ne

114 transient water networks that could support proton transfer from the N phase toward heme a via neutr

115 ydride or dihydrogen complex, resulting from proton transfer from the pendant amine to the metal hydr

116 ansfer from the phenol to the anthracene and proton transfer from the phenol to the pyridine, forming

117 (LEPT) state, in which both the electron and proton transfer from the phenol to the pyridine.

118 been experimentally determined by monitoring proton transfer from the protonated mono- and biradicals

119 c cleavage of the O-O bond is triggered by a proton transfer from the proximal to the distal oxygen a

120 ion step, however, is greatly facilitated by proton transfer from the reacting NH3 to the solvent.

121 We also find that proton transfer from the transient FMNH(*) to a nearby c

122 ts (tau = 65 ps), followed by intermolecular proton transfer from TsOH (tau approximately 3 ns for th

123 transfer from tyrosine to Ru(bpy)(3)(3+) and proton transfer from tyrosine to a hydrogen phosphate di

124 ations, we elucidate the key role of surface proton transfers from co-adsorbed H2O molecules in activ

125 vel data acquisition method based on ion-ion proton transfer, herein termed proton transfer charge re

126 ses through 1,2-addition, 1,4-intramolecular proton transfer, Huisgen 1,3-dipolar cycloaddition, and

127 ably, arginine R148 facilitate bidirectional proton transfer in [FeFe]-hydrogenases.

128 Long-range electron transfer is coupled to proton transfer in a wide range of chemically and biolog

129 probe water molecule catalyzed excited-state proton transfer in aqueous solution.

130 voltage changes associated with electron and proton transfer in cytochrome c oxidase could, in princi

131 Proton transfer in cytochrome c oxidase from the cellula

132 Li2CO3)8H](+), the mechanism and kinetics of proton transfer in lithium molten carbonate (MC) were in

133 a)Ind undergoes N(1)-H to N(6) long-distance proton transfer in neutral H2O, resulting in normal (340

134 for the first time the fundamental of triple proton transfer in pure water for azaindoles as well as

135 nduced by UV excitation triggers interstrand proton transfer in the alternating miniduplex containing

136 We describe ultrafast proton transfer in the ground electronic state triggered

137 olves the unprecedentedly fast multiposition proton transfer in the intermediate adducts of acetylene

138 otope effect (k (H)/k (D) ~ 1.7), suggesting proton transfer in the rate-limiting step.

139 (Hox), the presented data support continuous proton transfer in the reduced state (Hred).

140 nprecedented detail, including the degree of proton transfer in the transition state.

141 und I (i.e. FeO(3) (+)) or, alternatively, a proton transfer-independent nucleophilic ferric peroxo a

142 on as both a redox enzyme and a proton pump, proton transfer into the protein toward the BNC or towar

143 Although the second proton transfer involves the formation of a singlet dira

144 PR(2)) group on an unsaturated substrate and proton transfer involving the metal hydride yields the p

145 uces Tyr-O radicals by combined electron and proton transfer involving the phenol and carboxyl groups

146 gating is tightly coupled to intramolecular proton transfers involving the same residues that define

147 multiple iterations of ion accumulation and proton-transfer ion/ion reaction can be performed prior

148 rom total lipid extracts utilizing gas-phase proton-transfer ion/ion reactions.

149 Intramolecular electron-induced proton transfer is a similar process that occurs within

150 tent with a mechanism in which rate-limiting proton transfer is an important contributor.

151 acid support a transition state in which the proton transfer is complete.

152 Proton transfer is linked to a canonical photocycle typi

153 g radical through stepwise electron transfer/proton transfer is not as favorable as alternative mecha

154 nges are normally categorized by whether the proton transfer is occurring during the rate-limiting st

155 In comparison, our understanding of proton transfer is poor.

156 rough iron-sulfur clusters, the mechanism of proton transfer is still debated.

157 It is confirmed that proton transfer is the central event in the spectrochemi

158 anion followed by barrierless intramolecular proton transfer leads to the final product.

159 The calculations revealed a local electron-proton transfer (LEPT) state, in which both the electron

160 Amide proton transfer magnetic resonance imaging (APT MRI) hol

161 findings advance our understanding of amide proton transfer magnetic resonance imaging (APT MRI) of

162 h African lamb meat and fat were measured by proton-transfer mass spectrometry (PTR-MS) to evaluate i

163 This relayed proton transfer may exist in other ion channels and has

164 However, fundamental issues of proton transfer mechanism via 2D membranes are unclear a

165 ron transfer, and single electron transfer - proton transfer mechanisms.

166 4 mutations have a drastic effect on D97 and proton transfer mediated through H75.

167 H2Q serves as an electron-proton transfer mediator (EPTM) that enables electrochem

168 dol reaction followed by fast intramolecular proton transfer occurs to give the ring-opened aldehyde.

169 The importance of proton transfer on the intrinsic fluorescence observed i

170 effect arising from the strong dependence of proton transfer on the proton donor-acceptor distance pr

171 different photochemical reactions, including proton transfer or hydride transfer.

172 th a photoactivation mechanism that involves proton transfer or proton-coupled electron transfer from

173 inst initial outer-sphere electron transfer, proton transfer, or substrate coordination.

174 all of the residues involved in the electron/proton transfer pathway are directly observed.

175 Our structure further reveals the electron/proton transfer pathway for succinate oxidation by menaq

176 n transfer/proton transfer/electron transfer/proton transfer pathway, with H(2) released from the pro

177 s than 0.02 A correspondingly shortening the proton transfer pathway.

178 ow for this to provide the means to create a proton transfer pathway.

179 aspartate) in either of two positions in the proton-transfer pathway retain significant activity and

180 Three possible proton transfer pathways (D, K, and H channels) have bee

181 The regulation of competitive proton transfer pathways has been established to be esse

182 Importantly, the electron and proton transfer pathways in [FeFe]-hydrogenases are well

183 e proton transfer along structurally defined proton-transfer pathways.

184 dissociated proton, where we also suggest a proton transfer process between one of the photoacids to

185 chanistic viewpoint, a two-step coordination/proton transfer process for N-H activation is shown to b

186 ures, these findings enable us to follow the proton transfer process of the entire acylation reaction

187 e and are able to capture the intramolecular proton transfer process.

188 results in a complex cascade of photoinduced proton transfer processes and can be interpreted by the

189 Fast stepwise electron transfer and proton transfer processes were proposed to account for t

190 g photoswitch in water and enable controlled proton-transfer processes for diverse applications.

191 lude intra- and intermolecular electron- and proton-transfer processes, as well as photochromic react

192 )Trp), which exhibits unique water-catalyzed proton-transfer properties, AnsA and AnsB are shown to h

193 nwhile have the excited-state intramolecular proton transfer property.

194 ctrochemistry, which suggests a stepwise one proton transfer (PT) and two electron transfer (ET) proc

195 onally, we have investigated the dynamics of proton transfer (PT) by a variety of methods including d

196 A common approach to speeding up proton transfer (PT) by molecular catalysts is manipulat

197 le water molecule in the active site enables proton transfer (PT) from the cross-linked tyrosine to a

198 ction pathways: one involves nearly complete proton transfer (PT) from the phenol to the peroxo ligan

199 ological ET often occurs simultaneously with proton transfer (PT) in order to avoid the high-energy,

200 re complicated by the challenge of following proton transfer (PT) in these large molecules.

201 he 1,3-dinitrobenzene isomer showed a higher proton transfer rate constant ( approximately 25 M(-1) s

202 be built into a highly efficient PEM with a proton transfer rate of seven orders of magnitude higher

203 ion and sluggish proton flux produces O2(-), proton transfer rates commensurate with O-O bond breakin

204 Proton Transfer Reaction - Mass Spectrometry (PTR-MS) is

205 The heat of protonation, deprotonation, and proton transfer reaction as well as the capability of an

206 ng-field ionization and to track the primary proton transfer reaction giving rise to the formation of

207 LDH, the concerted mechanism of the hydride-proton transfer reaction is not altered.

208 est Method 33A (OTM 33A) and a fast-response proton transfer reaction mass spectrometer to make direc

209 y of the emerging non-destructive technique, proton transfer reaction mass spectrometry (PTR-MS), was

210 action products that were investigated using proton transfer reaction mass spectrometry (PTR-MS).

211 Proton transfer reaction mass spectrometry is a useful t

212 echniques, particularly the well-established proton transfer reaction mass spectrometry, PTR-MS, and

213 Proton transfer reaction quadrupole mass spectrometry (P

214 ft turbine engines were investigated using a proton transfer reaction time-of-flight mass spectromete

215 mass-normalized fluxes were estimated with a Proton Transfer Reaction Time-of-Flight Mass Spectromete

216 ied, together with multiple VOCs measured by proton transfer reaction time-of-flight mass spectrometr

217 se VOC masses were tentatively identified by Proton Transfer Reaction Time-of-Flight Mass Spectrometr

218 ncentrations in good agreement with benchtop proton transfer reaction time-of-flight mass spectrometr

219 different apple cultivars was studied using proton transfer reaction time-of-flight mass spectrometr

220 A sampling setup coupled to PTR-ToF-MS (Proton Transfer Reaction Time-of-Flight Mass Spectrometr

221 Using PTR-ToF-MS (Proton Transfer Reaction Time-of-Flight Mass Spectrometr

222 ques to an enzyme designed for an elementary proton transfer reaction, we show how directed evolution

223 ection (GC-FID) and in dynamic conditions by Proton Transfer Reaction- Mass Spectrometry (PTR-MS).

224 and nanoplastics based on thermal desorption-proton transfer reaction-mass spectrometry.

225 cas, Southeast Asia) were investigated using Proton Transfer Reaction-Quadrupole interface-Time of Fl

226 s were analyzed by six different techniques: Proton Transfer Reaction-Time of Flight-Mass Spectrometr

227 eveloped and characterized the novel PTR3, a proton transfer reaction-time-of-flight mass spectromete

228 IF) in the reaction region (drift tube) of a proton transfer reaction-time-of-flight-mass spectromete

229 luding nondissociative electron transfer and proton transfer reaction.

230 A proton-transfer reaction between squaric acid (H(2)sq) a

231 tationally designed enzyme for an elementary proton-transfer reaction by nearly 4 orders of magnitude

232 velength aethalometer and a high-sensitivity proton-transfer reaction mass spectrometer installed at

233 bilization with spin traps and analysis with proton-transfer reaction mass spectrometry.

234 A proton-transfer-reaction mass spectrometer measured time

235 2017 , 89 , 10889 - 10897 ) how a proton-transfer-reaction mass spectrometry (PTR-MS) anal

236 e, 2,3-hexanedione, octanal and linalool) by proton-transfer-reaction mass spectrometry (PTR-MS).

237 headspace experiments on pig manure, we used proton-transfer-reaction mass spectrometry and cavity ri

238 sis of Aerosol Online") particle inlet and a proton-transfer-reaction time-of-flight mass spectromete

239 le organic compound (VOC) concentrations via proton-transfer-reaction time-of-flight mass spectrometr

240 zed by near-infrared-spectrometry (NIRS), by proton-transfer-reaction time-of-flight mass-spectrometr

241 Gas-phase ion-ion proton transfer reactions (PTR), which reduce the charge

242 In all ChRs investigated so far, proton transfer reactions and hydrogen bond changes are

243 uperb probe to obtain structural details for proton transfer reactions in biological systems at a tru

244 Furthermore, the order of the associated two proton transfer reactions is predicted to be different i

245 ke subunits in complex I that enable lateral proton transfer reactions on a microsecond time scale.

246 n the past to probe the dynamics of internal proton transfer reactions taking place during the functi

247 echanism of action of the modifiers includes proton transfer reactions through oxonium ion formation.

248 Competition between hydrogen bonding and proton transfer reactions was studied for systems compos

249 ng hydrogen-deuterium exchange, ion-molecule proton transfer reactions, and covalent modification of

250 , to inhibit the progression of ion/molecule proton transfer reactions, the product ions must be remo

251 differentiation between exo- and endothermic proton transfer reactions.

252 Here, we use cation-to-anion proton-transfer reactions (CAPTR) to reduce the charge s

253 ydrogenase were probed using cation-to-anion proton-transfer reactions (CAPTR), ion mobility, mass sp

254 m a single protein precursor or multiple ETD/proton-transfer reactions (PTR) reaction periods.

255 ion of saturated hydrocarbons via exothermic proton-transfer reactions involving highly acidic, proto

256 The investigated coupling of electron- and proton-transfer reactions is reminiscent of the operatio

257 gests that water exchange will influence the proton-transfer reactions underlying the acid/base react

258 High abundance of proton-transfer reagent ions was observed with relativel

259 t; however, the exact mechanism of catalytic proton transfer remained inconclusive.

260 e (FMN) dependent, implicating an additional proton transfer role for FMN in turnover of NO.

261 sfer (SPLET), and single electron transfer - proton transfer (SET-PT) mechanisms of 5CQA in benzene,

262 The rate of the water-catalyzed proton transfer shows a prominent H/D kinetic isotope ef

263 We argue that the final proton transfer step in the mechanism is responsible for

264 The third electron/proton transfer step is the bottleneck for water product

265 termediate 2 unstable against a preferential proton-transfer step at 25 degrees C leading to the gene

266 lectron-transfer process in which the second proton-transfer step yields the pyridinium cation detect

267 band and call for a reevaluation of the last proton transfer steps in bacteriorhodopsin.

268 ts occurs through a sequence of electron and proton transfer steps, the resulting photoproduct decays

269 s on the long-range coupling of electron and proton transfer steps.

270 eutral H2O, resulting in normal (340 nm) and proton-transfer tautomer (480 nm) emissions with an over

271 s that are displaced upon metal binding, the proton transfer that is coupled with electron transfer i

272 termediate state between photoexcitation and proton transfer that lives for 3 ps.

273 Considering the extent of proton transfer, the paraelectric (PE) state can be form

274 Proton transfer through membrane-bound ion channels is m

275 st redox state in its catalytic cycle, where proton transfer through the K-channel, from K362 to Y288

276 During proton transfer to a basic support hydroxyl group, elect

277 re-equilibrium electron transfer followed by proton transfer to a water or small water cluster as the

278 to a proximal radical cation in concert with proton transfer to a weak Bronsted base.

279 ter-sphere oxidant coupled to intramolecular proton transfer to a well-positioned proton acceptor.

280 y also highlights the kinetic challenges for proton transfer to catalytic intermediates in organic me

281 rence ( approximately 36 kcal/mol), favoring proton transfer to formate, is offset by the gain in int

282 ium/aryl carbanion) undergoes intramolecular proton transfer to generate a more stable S-aryl sulfur

283 ermolecular chemical step involving a second proton transfer to give the E2PT product.

284 hich thermodynamically disfavors a concerted proton transfer to H2O.

285 imaging technique, from charge transfer and proton transfer to nucleophilic substitution and elimina

286 tions show increasingly favorable pore-phase proton transfer to pyridine in the order: water < aceton

287 tonated E286, which would in principle allow proton transfer to the BNC, but no proton pumping until

288 r channel at the subunit interface for rapid proton transfer to the bulk solvent.

289 n shift from carbon-carbon bond formation to proton transfer to the catalyst's conjugate base.

290 singly deprotonated [CL - H](-) species via proton transfer to the corresponding [CL - 2H](2-) diani

291 roceeds via an electron transfer followed by proton transfer to the Fe(III)-O(2)(-) species.

292 transfer to ferrocenium oxidants coupled to proton transfer to various pyridine bases.

293 n acidic solutions reveals the importance of proton transfers to both carbon and oxygen in the overal

294 s chemical barrier involves both hydride and proton transfers to pyruvate to form l-lactate, using re

295 ollowed by a rate controlling amine assisted proton transfer toward the singly substituted product.

296 arge-transfer state drives sequential double proton transfer: Tyr8 transfers a proton to the interven

297 his transition state, the new O-H bond after proton transfer undergoes several vibrations before heav

298 peptide cations experience both electron and proton transfers upon photoexcitation, proving an amenab

299 s O-O bond formation via intramolecular atom-proton transfer with a calculated barrier of only 9.1 kc

300 d to support an initial, slow, and concerted proton transfer with release of isobutylene, followed by