Hydrophobic vitamin B<sub>12</sub>. Part 6. Carbon-skeleton rearrangement via formation of host–guest complexes derived from an ‘octopus’ azaparacyclophane and hydrophobic vitamin B<sub>12</sub>derivatives: a novel holoenzyme model system

Murakami, Yukito; Hisaeda, Yoshio; Kikuchi, Jun; Ohno, Teruhisa; Suzuki, Masashi; Matsuda, Yoshihisa; Matsuura, Tomoya

doi:10.1039/p29880001237

Cited by 26 publications

(14 citation statements)

References 8 publications

(12 reference statements)

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“…The yield of acetyl-migration product was significantly increased in HSA as compared with those in methanol and benzene. This result is similar to that for the vesicle-type or the cyclophane-type artificial B 12 enzyme systems as reported previously [3,9]. The 1,2-migration of the electron-withdrawing group arises both from suppression of molecular motion and desolvation effects on the alkylated hydrophobic vitamin B 12 in HSA.…”

Section: Article In Presssupporting

confidence: 76%

“…Preparation of 2-(imidazol-4-yl)-N-[5-(dimethylamino)-1-naphthylsulphonyl]ethylamine (dansylhistamine) as a fluorescent probe has been reported previously [9]. 2-Acetyl-2-ethoxycarbonylpropane, 2-acetyl-1-ethoxycarbonylpropane, and 1-acethyl-2-ethoxycarbonylpropane were prepared as a substrate and authentic samples for the reaction products after the procedure reported previously [10].…”

Section: Methodsmentioning

confidence: 99%

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Organic/inorganic hybrid nanomaterials with vitamin B₁₂functions

Hisaeda

Masuko

Hanashima

et al. 2006

Science and Technology of Advanced Materials

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A hybrid nanomaterial was prepared by human serum albumin (HSA) and vitamin B 12 derivatives. The incorporation of hydrophobic vitamin B 12 derivatives, which have ester groups in place of the peripheral amide moieties of the natural cobalamin, into HSA is primarily controlled by the hydrophobicity of the peripheral ester groups. Microenvironmental property around the hydrophobic vitamin B 12 in HSA was examined by fluorescence and fluorescence polarization measurements. The hydrophobic vitamin B 12 itself in HSA is in a microenvironment equivalent in medium polarity to dichloromethane. The molecular motion of hydrophobic vitamin B 12 in HSA was markedly suppressed under such microenvironmental conditions. Carbon-skeleton rearrangement reaction of an alkyl radical derived from an alkyl ligand bound to the hydrophobic vitamin B 12 was markedly favored in HSA aqueous solution, relative to the reactions in methanol and benzene. The 1,2-migration of the electron-withdrawing group arises from both the suppression of molecular motion and desolvation effects on the alkylated hydrophobic vitamin B 12 in HSA. r

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Section: Article In Presssupporting

confidence: 76%

Section: Methodsmentioning

confidence: 99%

Organic/inorganic hybrid nanomaterials with vitamin B₁₂functions

Hisaeda

Masuko

Hanashima

et al. 2006

Science and Technology of Advanced Materials

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“…* Cited from ref. 28. Single-compartment vesicles of N+CSAla2Cl6 (5.0 x rnol dm-3) in aqueous phosphate-borate buffer (0.05 mol dm-3; pH 9.2).…”

Section: Incorporationmentioning

confidence: 99%

Hydrophobic vitamin B12. Part 9. An artificial holoenzyme composed of hydrophobic vitamin B12 and synthetic bilayer membrane for carbon-skeleton rearrangements

Murakami¹,

Hisaeda²,

Ohno³

1991

J. Chem. Soc., Perkin Trans. 2

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The incorporation of hydrophobic vitamin B, , derivatives, which have ester groups in place of the peripheral amide moieties of the naturally occurring vitamin B12, into single-compartment vesicles composed of synthetic lipids having an alanyl residue in the single-chain segment, is primarily controlled b y the hydrophobicity of the peripheral ester groups. Such incorporation into vesicles of another synthetic lipid, having a histidyl residue in place of an alanyl residue, was much enhanced when coordination was allowed to take place between the nuclear cobalt of the hydrophobic vitamin B, , and the imidazolyl moiety of the lipid. Microenvironmental properties around heptapropyl cobyrinate derivatives placed in single-compartment vesicles of the former lipid were examined b y electronic, fluorescence and fluorescence polarization measurements as well as b y differential scanning calorimetry. The hydrophobic vitamin B, , was incorporated into the intramembrane domain composed of assembly of the single-chain segment of each lipid molecule, and its molecular motion was markedly suppressed under such microenvironmental conditions. Carbon-skeleton rearrangement reactions of alkyl ligands bound to heptapropyl cobyrinate were markedly favoured in the single-compartment vesicle, relative to the reactions in methanol and benzene, under anaerobic photolysis conditions at ordinary temperatures. The 1,2-migration of electron-withdrawing groups, such as acetyl, cyano, carboxylic ester and thioester, apparently arises both from suppression of molecular motion and desolvation effects operating on the alkylated hydrophobic vitamin B, , in the vesicle. Finally, the catalytic mediator, constituted with heptapropyl cobyrinate perchlorate and the single-compartment vesicle in aqueous media, was coupled with a substrate-activation system, composed of atmospheric oxygen and vanadium( 111) ions, to establish a real artifical holoenzyme. 2 -Acety I -2 -et hoxycarbonyl pro pa ne, 1 -acety I -1et hoxycarbonylethane were converted catalytically into the corresponding rearrangement products under aerobic photolysis conditions at 20 "C. A plausible reaction mechanism for the catalytic reaction is discussed. 2 -cya no -2 -et hoxycarbonyl propa ne and Coenzyme B ,-dependent enzymes which catalyse isomerization reactions, leading to the intramolecular exchange of a functional group (X) and a hydrogen atom between neighbouring carbon atoms [eqn. (l)], have received much attention because of the novel nature of these reactions from the viewpoints of organic and organometallic chemistry. Various cobalt complexes have been synthesized as vitamin B , model complexes, and their physicochemical properties and catalytic performance have been investigated in attempts to clarify mechanisms involved in vitamin B , ,-dependent enzymatic reactions. ' Recently, these complexes have been extensively * This synthesis was carried out by Mr. Xi-Ming Song of this laboratory.

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“…Furthermore, we explored a methyl-transfer reaction from methyl tosylate (TsOCH 3 ) to 1-octanethiol under controlled-potential electrolyses at À1.0 V vs. Ag/AgCl at 50°C with the hydrophobic vitamin B 12 (heptamethyl cobyrinate perchlorate, [Cob(II)7C 1 ester]ClO 4 ) [25][26][27][28], which has ester groups in place of the peripheral amide moieties of the naturally occurring cobalamin and shows excellent catalytic ability in organic solvents [29], as the catalyst. The formation and formally heterolytic cleavage of the Co-CH 3 bond in the catalyst is confirmed to be an indispensable process in this catalytic cycle.…”

Section: Introductionmentioning

confidence: 99%

Methyl-transfer reaction to alkylthiol catalyzed by a simple vitamin B12 model complex using zinc powder

Pan¹,

Tahara²,

Masuko³

et al. 2011

Inorganica Chimica Acta

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Hydrophobic vitamin B₁₂. Part 6. Carbon-skeleton rearrangement via formation of host–guest complexes derived from an ‘octopus’ azaparacyclophane and hydrophobic vitamin B₁₂derivatives: a novel holoenzyme model system

Cited by 26 publications

References 8 publications

Organic/inorganic hybrid nanomaterials with vitamin B₁₂functions

Organic/inorganic hybrid nanomaterials with vitamin B₁₂functions

Hydrophobic vitamin B12. Part 9. An artificial holoenzyme composed of hydrophobic vitamin B12 and synthetic bilayer membrane for carbon-skeleton rearrangements

Methyl-transfer reaction to alkylthiol catalyzed by a simple vitamin B12 model complex using zinc powder

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Hydrophobic vitamin B12. Part 6. Carbon-skeleton rearrangement via formation of host–guest complexes derived from an ‘octopus’ azaparacyclophane and hydrophobic vitamin B12derivatives: a novel holoenzyme model system

Cited by 26 publications

References 8 publications

Organic/inorganic hybrid nanomaterials with vitamin B12functions

Organic/inorganic hybrid nanomaterials with vitamin B12functions

Hydrophobic vitamin B12. Part 9. An artificial holoenzyme composed of hydrophobic vitamin B12 and synthetic bilayer membrane for carbon-skeleton rearrangements

Methyl-transfer reaction to alkylthiol catalyzed by a simple vitamin B12 model complex using zinc powder

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Product

Resources

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Hydrophobic vitamin B₁₂. Part 6. Carbon-skeleton rearrangement via formation of host–guest complexes derived from an ‘octopus’ azaparacyclophane and hydrophobic vitamin B₁₂derivatives: a novel holoenzyme model system

Organic/inorganic hybrid nanomaterials with vitamin B₁₂functions

Organic/inorganic hybrid nanomaterials with vitamin B₁₂functions