1
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Sari H, Al-Obaidi FN, Macit M, Atabey H. Study of the Coordination Properties of 1,2-Bis(2,6-dimethphenylamino) Glyoxime and Determine the Stability Constant of Its Complexes with Ni(II), Cu(II) and Zn(II) Metal Ions in Solution. J SOLUTION CHEM 2011. [DOI: 10.1007/s10953-011-9733-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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2
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Devecİ P, Özcan E, Taner Bİ, Arslan Ö. Synthesis and complexation of two new phenylaminoglyoxime ligands. J COORD CHEM 2010. [DOI: 10.1080/00958970701439396] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Pervİn Devecİ
- a Faculty of Arts and Sciences, Department of Chemistry , Selcuk University , 42031, Konya, Turkey
| | - Emİne Özcan
- a Faculty of Arts and Sciences, Department of Chemistry , Selcuk University , 42031, Konya, Turkey
| | - Bİlge Taner
- a Faculty of Arts and Sciences, Department of Chemistry , Selcuk University , 42031, Konya, Turkey
| | - Ömer Arslan
- a Faculty of Arts and Sciences, Department of Chemistry , Selcuk University , 42031, Konya, Turkey
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3
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Alzoubi BM, Vidali F, Puchta R, Dücker-Benfer C, Felluga A, Randaccio L, Tauzher G, van Eldik R. Mechanistic behaviour of alkylcobaloximes and imino-oxime complexes related to vitamin B12. Dalton Trans 2009:2392-9. [DOI: 10.1039/b816511d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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4
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Şekerci M. Synthesis of (Z,Z)-1, 2-dihydroxyimino-3, 6-diamlno-8, 9-O,O-cyclopentylidenenonane-8, 9-diol and Its Complexes with Copper(II), Nickel(II), Cobalt(II) and Uranyl(VI). ACTA ACUST UNITED AC 2008. [DOI: 10.1080/00945710009351757] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Memet Şekerci
- a Firat University, Faculty of Arts and Sciences, Chemistry Department , 23119 , Elaziĝ , Turkey
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5
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Coşkun A, Yılmaz F, Akgemci EG. Synthesis, characterization and electrochemical investigation of a novel vic-dioxime ligand and its some transition metal complexes. J INCL PHENOM MACRO 2007. [DOI: 10.1007/s10847-007-9389-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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6
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Abstract
This review describes enzymes that contain radicals and/or catalyze reactions with radical intermediates. Because radicals irreversibly react with dioxygen, most of these enzymes occur in anaerobic bacteria and archaea. Exceptions are the families of coenzyme B(12)- and S-adenosylmethionine (SAM)-dependent radical enzymes, of which some members also occur in aerobes. Especially oxygen-sensitive radical enzymes are the glycyl radical enzymes and 2-hydroxyacyl-CoA dehydratases. The latter are activated by an ATP-dependent one-electron transfer and act via a ketyl radical anion mechanism. Related enzymes are the ATP-dependent benzoyl-CoA reductase and the ATP-independent 4-hydroxybenzoyl-CoA reductase. Ketyl radical anions may also be generated by one-electron oxidation as shown by the flavin-adenine-dinucleotide (FAD)- and [4Fe-4S]-containing 4-hydroxybutyryl-CoA dehydratase. Finally, two radical enzymes are discussed, pyruvate:ferredoxin oxidoreductase and methane-forming methyl-CoM reductase, which catalyze their main reaction in two-electron steps, but subsequent electron transfers proceed via radicals.
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Affiliation(s)
- Wolfgang Buckel
- Fachbereich Biologie, Philipps-Universität, D-35032 Marburg, Germany.
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7
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Taş E, Çukurovali A, Kaya M. SYNTHESIS OF A NEW GLYOXIME DERIVATIVE, CHARACTERIZATION AND INVESTIGATION OF ITS COMPLEXES WITH NI(II), CO(II), CU(II) AND UO2(VI) METALS. J COORD CHEM 2006. [DOI: 10.1080/00958979808022885] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Eşlref Taş
- a Department of Chemistry, Faculty of Arts , Science University of Firat , Elaziĝ, Turkey
| | | | - Mehmet Kaya
- a Department of Chemistry, Faculty of Arts , Science University of Firat , Elaziĝ, Turkey
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8
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Rangel M, Leite A, Gomes J, de Castro B. Photolysis Secondary Products of Cobaloximes and Imino/Oxime Compounds Controlled by Steric Hindrance Imposed by the Lewis Base. Organometallics 2005. [DOI: 10.1021/om0580046] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Maria Rangel
- REQUIMTE/Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Portugal, and REQUIMTE/Departamento de Química, Faculdade de Ciências do Porto, Portugal
| | - Andreia Leite
- REQUIMTE/Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Portugal, and REQUIMTE/Departamento de Química, Faculdade de Ciências do Porto, Portugal
| | - João Gomes
- REQUIMTE/Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Portugal, and REQUIMTE/Departamento de Química, Faculdade de Ciências do Porto, Portugal
| | - Baltazar de Castro
- REQUIMTE/Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Portugal, and REQUIMTE/Departamento de Química, Faculdade de Ciências do Porto, Portugal
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9
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Ohkubo K, Fukuzumi S. Electron-Transfer Oxidation of Coenzyme B12 Model Compounds and Facile Cleavage of the Cobalt(IV)−Carbon Bond via Charge-Transfer Complexes with Bases. A Negative Temperature Dependence of the Rates. J Phys Chem A 2005; 109:1105-13. [PMID: 16833419 DOI: 10.1021/jp0453008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The electron-transfer oxidation and subsequent cobalt-carbon bond cleavage of vitamin B12 model complexes were investigated using cobaloximes, (DH)2Co(III)(R)(L), where DH- = the anion of dimethylglyoxime, R = Me, Et, Ph, PhCH2, and PhCH(CH3), and L = a substituted pyridine, as coenzyme B12 model complexes and [Fe(bpy)3](PF6)3 or [Ru(bpy)3](PF6)3 (bpy = 2,2'-bipyridine) as a one-electron oxidant. The rapid one-electron oxidation of (DH)2Co(III)(Me)(py) (py = pyridine) with the oxidant gives the corresponding Co(IV) complexes, [(DH)2Co(IV)(Me)(py)]+, which were well identified by the ESR spectra. The reorganization energy (lambda) for the electron-transfer oxidation of (DH)2Co(Me)(py) was determined from the ESR line broadening of [(DH)2Co(Me)(py)]+ caused by the electron exchange with (DH)2Co(Me)(py). The lambda value is applied to evaluate the rate constants of photoinduced electron transfer from (DH)2Co(Me)(py) to photosensitizers in light of the Marcus theory of electron transfer. The Co(IV)-C bond cleavage of [(DH)2Co(Me)(py)]+ is accelerated significantly by the reaction with a base. The overall activation energy for the second-order rate constants of Co(IV)-C bond cleavage of [(DH)2Co(IV)(Me)(py)]+ in the presence of a base is decreased by charge-transfer complex formation with a base, which leads to a negative activation energy for the Co(IV)-C cleavage when either 2-methoxypyridine or 2,6-dimethoxypyridine is used as the base.
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Affiliation(s)
- Kei Ohkubo
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, SORST, Japan Science and Technology Agency, Suita, Osaka 565-0871, Japan
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10
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Hamza MSA, Zou X, Banka R, Brown KL, van Eldik R. Kinetic and thermodynamic studies on ligand substitution reactions and base-on/base-off equilibria of cyanoimidazolylcobamide, a vitamin B12 analog with an imidazole axial nucleoside. Dalton Trans 2005:782-7. [PMID: 15702190 DOI: 10.1039/b414092c] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ligand substitution reactions of the vitamin B12 analog cyanoimidazolylcobamide, CN(Im)Cbl, with cyanide were studied. Cyanide substitutes imidazole (Im) in the alpha-position more slowly than it substitutes dimethylbenzimidazole in cyanocobalamin (vitamin B12). The kinetics of the displacement of Im by CN- showed saturation behaviour at high cyanide concentration; the limiting rate constant was found to be 0.0264 s(-1) at 25 degrees C and is characterized by the activation parameters: DeltaH(not =) = 111 +/- 2 kJ mol(-1), DeltaS(not =) = +97 +/- 6 J K(-1) mol(-1), and DeltaV(not =) = +9.3 +/- 0.3 cm3 mol(-1). These parameters are interpreted in terms of an I(d) mechanism. The equilibrium constant for the reaction of CN(Im)Cbl with CN- was found to be 861 +/- 75 M(-1), which is significantly less than that obtained for the reaction of cyanocobalamin with CN- (viz. 10(4) M(-1)). pKbase-off for the base-on/base-off equilibrium was determined spectrophotometrically and found to be 0.99 +/- 0.05, which is about 0.9 pH units higher than that obtained previously in the case of cyanocobalamin. In addition, the kinetics of the base-on/base-off reaction was studied using a pH-jump technique and the data obtained revealed evidence for an acid catalyzed reaction path. The results obtained in this study are discussed in reference to those reported previously for cyanocobalamin.
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Affiliation(s)
- Mohamed S A Hamza
- Institute for Inorganic Chemistry, University of Erlangen-Nurnberg, Egerlandstr.1, 91058, Erlangen, Germany
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11
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MASARWA ALEXANDRA, MEYERSTEIN DAN. PROPERTIES OF TRANSITION METAL COMPLEXES WITH METAL–CARBON BONDS IN AQUEOUS SOLUTIONS AS STUDIED BY PULSE RADIOLYSIS. ADVANCES IN INORGANIC CHEMISTRY 2004. [DOI: 10.1016/s0898-8838(03)55005-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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12
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Chen H, Li G, Zhang FF, Sun L, Chen HL, Zhang SY. Co-C bond dissociation energy and reaction volume change of 2',5'-dideoxyadenosylcobalamin studied by laser-induced time-resolved photoacoustic calorimetry. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2003; 59:2767-2774. [PMID: 14499837 DOI: 10.1016/s1386-1425(03)00057-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Time resolved photoacoustic calorimetry (PAC) was applied to a study of the photolysis of a coenzyme B(12) analog 2',5'-dideoxyadenosylcobalamin, which lacks an -OH group at the 2' position of ribofuranose ring. In aqueous solution, we report for the first time the quantum yield Phi(d) (0.25+/-0.02), Co-C bond dissociation energy (BDE; 31.8+/-2.5 kcal mol(-1)) and reaction volume change deltaV(R) (6.5+/-0.5 ml mol(-1)) due to conformation changes of the corrin ring and its side chains accompanying the cleavage of the Co-C bond. These values for the analog are very similar to those for the natural cofactor. Based our results and previous studies, a possible explanation for the similarity in their structure and properties versus the large difference in their enzymatic activity is discussed.
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Affiliation(s)
- Hao Chen
- Department of Chemistry, Nanjing University, Hankou Road 22, Nanjing 210093, People's Republic of China
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13
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Lancelot SF, Cozens FL, Schepp NP. Substituent effects on the ionization reaction of beta-mesylate phenethyl radicals. Org Biomol Chem 2003; 1:1972-9. [PMID: 12945782 DOI: 10.1039/b301959d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of beta-methanesulfonate phenethyl radicals bearing a range of electron donating and withdrawing aromatic substituents were generated and studied in a variety of solvent mixtures using nanosecond laser flash photolysis. Rate constants for the formation of the corresponding styrene radical cation via heterolytic loss of the beta-mesylate leaving group were measured using time-resolved absorption spectroscopy. The ionization reaction was investigated in a variety of solvents and solvent mixtures including 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,2-trifluoroethanol, acetonitrile, methanol and water. The influence of substituent electronic effect and solvent polarity on the kinetics of the beta-heterolysis reaction are discussed and assessed using the sigma+ Hammett parameter and Y(OMs) values, respectively. The small magnitude of m calculated for the formation of the 4-methoxystyrene radical cation by ionization of the mesylate group (m = 0.33) in aqueous methanol mixtures is compared to values obtained for the formation of the same radical cation via loss of chloride and bromide where m = 0.56 and m = 0.45, respectively.
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Affiliation(s)
- Sandy F Lancelot
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J3
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14
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Perry C, Fernandes M, Zou X, Valente E, Marques H. Probing the Nature of the CoIII Ion in Cobalamins − Spectroscopic and Structural Investigations of the Reactions of Aquacobalamin (Vitamin B12a) with Ambident Nucleophiles. Eur J Inorg Chem 2003. [DOI: 10.1002/ejic.200200600] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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15
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Affiliation(s)
- Fahmi Himo
- Theoretical Chemistry, Department of Biotechnology, Royal Institute of Technology, SCFAB, SE-106 91 Stockholm, Sweden
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16
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Uyemura M, Aida T. Steric control of organic transformation by a dendrimer cage: organocobalt dendrimer porphyrins as novel coenzyme B(12) mimics. J Am Chem Soc 2002; 124:11392-403. [PMID: 12236754 DOI: 10.1021/ja020687i] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Cobalt(II) complexes of poly(aryl ester) dendrimer porphyrins (m-[Gn]TPP)Co(II) and (p-[Gn]TPP)Co(II) (n = 0-3) underwent AIBN-initiated alkylation (AIBN = 2,2'-azobis(isobutyronitrile)) at the metal center with propargyl alcohol in CDCl(3) at 60 degrees C, where the dendritic substituents did not affect the overall conversion rate but selectivity of the alkylation. With the largest (m-[G3]TPP)Co(II), a single organocobalt(III) species (Co(III)-C(=CH(2))CH(2)OH, 4) was selectively formed in 91% yield, due to a steric protection of 4 by the large dendrimer cage from the access of another molecule of cobalt porphyrin species. In contrast, with other cobalt(II) porphyrins, isomerized compounds such as Co(III)-C(CH(3))=CHOH (5) and Co(III)-CH(CH(3))CHO (6) were formed in addition to 4. A stereochemical investigation with (m-[G3]TPP)Co(II) using AIBN-d(12), in place of nondeuterated AIBN, demonstrated that the alkylation (cobalt(III) hydride addition to propargyl alcohol) is selective to a trans adduct. Results also indicated that this addition step does not involve external activation of propargyl alcohol.
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Affiliation(s)
- Makoto Uyemura
- JST ERATO Nanospace Project, National Museum of Emerging Science and Innovation Building, 2-41 Aomi, Koto-ku, Tokyo 135-0064, Japan
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17
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Semialjac M, Schwarz H. Computational exploration of rearrangements related to the vitamin B12-dependent ethanolamine ammonia lyase catalyzed transformation. J Am Chem Soc 2002; 124:8974-83. [PMID: 12137553 DOI: 10.1021/ja020101s] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
DFT (B3LYP/6-31G) and ab initio molecular orbital theory (QCISD/cc-pVDZ) are used to investigate several possible mechanisms involving free radical intermediates as well as their protonated forms for processes related to the coenzyme B(12)-dependent rearrangement catalyzed by ethanolamine ammonia lyase. Two major types of rearrangements are discussed in detail, intramolecular migration and dissociation of the amine/ammonia groups, for both of which several scenarios are considered. According to the calculations, the complete dissociation of the migrating group and its subsequent association constitute an unlikely route for both the protonated and the unprotonated reactant because of the high-energy barriers (more than 23 kcal/mol) involved in these steps. Direct migration of the protonated amine group is far more favorable (10.4 kcal/mol) and therefore presents the most likely candidate for the actual enzymatic reaction. The calculations further imply that the direct loss of an ammonium cation (10.6 kcal/mol) represents a feasible pathway as well. Comparing the rearrangements for the aminoethanol radical and its protonated counterpart, in line with previous findings reported by Golding, Radom, and co-workers, we find that the migration of a protonated group is in general associated with lower energy barriers, suggesting that the actual enzyme substrate quite likely corresponds to (partially) protonated aminoethanol. As the extent of the substrate protonation/deprotonation by the active site of the enzyme may vary, the actual energy barriers are expected to range between the values calculated for the two extreme cases of a substrate, that is, the aminoethanol radical 2 and its fully protonated form 6.
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Affiliation(s)
- Marija Semialjac
- Institut für Chemie der Technischen Universität Berlin, D-10623 Berlin, Germany.
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18
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Eda M, Kamachi T, Yoshizawa K, Toraya T. Theoretical Study on the Mechanism of Catalysis of Coenzyme B12-Dependent Diol Dehydratase. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2002. [DOI: 10.1246/bcsj.75.1469] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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19
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Speranza G, Mueller B, Orlandi M, Morelli CF, Manitto P, Schink B. Mechanism of anaerobic ether cleavage: conversion of 2-phenoxyethanol to phenol and acetaldehyde by Acetobacterium sp. J Biol Chem 2002; 277:11684-90. [PMID: 11805106 DOI: 10.1074/jbc.m111059200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
2-Phenoxyethanol is converted into phenol and acetate by a strictly anaerobic Gram-positive bacterium, Acetobacterium strain LuPhet1. Acetate results from oxidation of acetaldehyde that is the early product of the biodegradation process (Frings, J., and Schink, B. (1994) Arch. Microbiol. 162, 199-204). Feeding experiments with resting cell suspensions and 2-phenoxyethanol bearing two deuterium atoms at either carbon of the glycolic moiety as substrate demonstrated that the carbonyl group of the acetate derives from the alcoholic function and the methyl group derives from the adjacent carbon. A concomitant migration of a deuterium atom from C-1 to C-2 was observed. These findings were confirmed by NMR analysis of the acetate obtained by fermentation of 2-phenoxy-[2-(13)C,1-(2)H(2)]ethanol, 2-phenoxy-[1-(13)C,1-(2)H(2)]ethanol, and 2-phenoxy-[1,2-(13)C(2),1-(2)H(2)]ethanol. During the course of the biotransformation process, the molecular integrity of the glycolic unit was completely retained, no loss of the migrating deuterium occurred by exchange with the medium, and the 1,2-deuterium shift was intramolecular. A diol dehydratase-like mechanism could explain the enzymatic cleavage of the ether bond of 2-phenoxyethanol, provided that an intramolecular H/OC(6)H(5) exchange is assumed, giving rise to the hemiacetal precursor of acetaldehyde. However, an alternative mechanism is proposed that is supported by the well recognized propensity of alpha-hydroxyradical and of its conjugate base (ketyl anion) to eliminate a beta-positioned leaving group.
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Affiliation(s)
- Giovanna Speranza
- Dipartimento di Chimica Organica e Industriale, Università degli Studi di Milano, and Centro di Studio per le Sostanze Organiche Naturali, CNR, via Venezian 21, I-20133 Milano, Italy.
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20
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Rangel M, Pereira E, Oliveira C, de Castro B. Characterization of the photolysis products of sec-butylcobaloximes with imidazole and benzimidazole bases. J Organomet Chem 2001. [DOI: 10.1016/s0022-328x(01)00854-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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21
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Smith DM, Golding BT, Radom L. Understanding the mechanism of B(12)-dependent diol dehydratase: a synergistic retro-push--pull proposal. J Am Chem Soc 2001; 123:1664-75. [PMID: 11456766 DOI: 10.1021/ja001454z] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ab initio molecular orbital theory is used to investigate the coenzyme B(12)-dependent reactions catalyzed by diol dehydratase. The key step in such reactions is believed to be a 1,2-hydroxyl migration, which occurs within free-radical intermediates. The barrier for this migration, if unassisted, is calculated to be too high to be consistent with the observed reaction rate. However, we find that "pushing" the migrating hydroxyl, through interaction with a suitable acid, is able to provide significant catalysis. This is denoted retro-push catalysis, the retro prefix signifying that the motion of the migrating group is in the direction opposite to the electron motion. Similarly, the "pulling" of the migrating group, through interaction of the spectator hydroxyl with an appropriate base, is found to substantially reduce the rearrangement barrier. Importantly, the combination of these two effects results in a barrier reduction that is notably greater than additive. This synergistic interplay of the push and the pull provides an attractive means of catalysis. Our proposed retro-push--pull mechanism leads to results that are consistent with isotope-labeling experiments, with experimental rate data, and with the crystal structure of the enzyme.
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Affiliation(s)
- D M Smith
- Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia
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22
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Theoretical studies of coenzyme B12-dependent carbon-skeleton rearrangements. THEORETICAL AND COMPUTATIONAL CHEMISTRY 2001. [DOI: 10.1016/s1380-7323(01)80006-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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23
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Gomes J, de Castro B. EPR characterization of the products formed after photolysis of [CoIII(Salen)(CH3)(H2O)] and [CoIII(SaltMe)(CH3)(H2O)] in the presence of N- and P-donor bases. Inorg Chem 2000; 39:1994-7. [PMID: 11428120 DOI: 10.1021/ic990919n] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J Gomes
- CEQUP/Departamento de Química, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal
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24
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Schurko RW, Wasylishen RE. Nitrogen-15 NMR Study of Solid Cobaloximes Containing 15N-Labeled Pyridine and Aniline. J Phys Chem A 2000. [DOI: 10.1021/jp994254m] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Robert W. Schurko
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J3
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25
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George P, Siegbahn PEM, Glusker JP, Bock CW. The Dehydration Step in the Enzyme-Coenzyme-B12 Catalyzed Diol Dehydrase Reaction of 1,2-Dihydroxyethane Utilizing a Hydrogen-Bonded Carboxylic Acid Group as an Additional Cofactor: A Computational Study. J Phys Chem B 1999. [DOI: 10.1021/jp9912962] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Philip George
- The Institute for Cancer Research, Fox Chase Cancer Center, 7701 Burholme Avenue, Philadelphia, Pennsylvania 19111, Department of Physics, University of Stockholm, Sweden, and Department of Chemistry, Philadelphia University, Henry Avenue and School House Lane, Philadelphia, Pennsylvania 19144
| | - Per E. M. Siegbahn
- The Institute for Cancer Research, Fox Chase Cancer Center, 7701 Burholme Avenue, Philadelphia, Pennsylvania 19111, Department of Physics, University of Stockholm, Sweden, and Department of Chemistry, Philadelphia University, Henry Avenue and School House Lane, Philadelphia, Pennsylvania 19144
| | - Jenny P. Glusker
- The Institute for Cancer Research, Fox Chase Cancer Center, 7701 Burholme Avenue, Philadelphia, Pennsylvania 19111, Department of Physics, University of Stockholm, Sweden, and Department of Chemistry, Philadelphia University, Henry Avenue and School House Lane, Philadelphia, Pennsylvania 19144
| | - Charles W. Bock
- The Institute for Cancer Research, Fox Chase Cancer Center, 7701 Burholme Avenue, Philadelphia, Pennsylvania 19111, Department of Physics, University of Stockholm, Sweden, and Department of Chemistry, Philadelphia University, Henry Avenue and School House Lane, Philadelphia, Pennsylvania 19144
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26
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Smith DM, Golding BT, Radom L. Toward a Consistent Mechanism for Diol Dehydratase Catalyzed Reactions: An Application of the Partial-Proton-Transfer Concept. J Am Chem Soc 1999. [DOI: 10.1021/ja990209g] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- David M. Smith
- Contribution from the Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia, and Department of Chemistry, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, U.K
| | - Bernard T. Golding
- Contribution from the Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia, and Department of Chemistry, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, U.K
| | - Leo Radom
- Contribution from the Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia, and Department of Chemistry, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, U.K
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27
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Smith DM, Golding BT, Radom L. On the Mechanism of Action of Vitamin B12: Theoretical Studies of the 2-Methyleneglutarate Mutase Catalyzed Rearrangement. J Am Chem Soc 1999. [DOI: 10.1021/ja9827245] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- David M. Smith
- Contribution from the Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia, and Department of Chemistry, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, UK
| | - Bernard T. Golding
- Contribution from the Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia, and Department of Chemistry, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, UK
| | - Leo Radom
- Contribution from the Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia, and Department of Chemistry, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, UK
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28
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Kadish KM, Boulas PL, Kisters M, Vogel E, Aukauloo AM, D'Souza F, Guilard R. Synthesis and Electrochemical Reactivity of sigma-Bonded and N-Substituted Cobalt Porphycenes. Inorg Chem 1998; 37:2693-2700. [PMID: 11670405 DOI: 10.1021/ic971534c] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The first synthesis and characterization of sigma-bonded and N-substituted cobalt porphycenes is reported. The investigated compounds are represented as (Pc)Co(R) and (N-CH(3)OEPc)CoCl, where R is CH(3) or C(6)H(5), Pc is the dianion of 2,3,6,7,12,13,16,17-octaethylporphycene (OEPc), 2,7,12,17-tetrapropylporphycene (TPrPc), or 2,7,12,17-tetraethyl-3,6,13,16-tetramethylporphycene (EtioPc), N-CH(3)OEPc is the monoanion of N-methyl-2,3,6,7,12,13,16,17-octaethylporphycene. Each sigma-bonded (Pc)Co(R) derivative can be reversibly reduced or oxidized by two electrons, but a slow migration of the sigma-bonded R group occurs following electrogeneration of [(Pc)Co(R)](+)()(*)() leading, as a final product, to an N-substituted cobalt(II) porphycene which is also electroactive and undergoes two reductions in PhCN. The singly reduced product of this reaction is formulated as a Co(II) pi-anion radical which undergoes a slow "back-migration" of the CH(3) group to regenerate (OEPc)Co(CH(3)).
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Affiliation(s)
- K. M. Kadish
- Department of Chemistry, University of Houston, Houston, Texas 77204-5641, Institut für Organische Chemie, Universität zu Köln, Greinstrasse 4, 50939 Köln, Germany, and Laboratoire d'Ingénierie Moléculaire pour la Séparation et les Applications des Gaz Associé au CNRS (LIMSAG), UMR 5633, Faculté des Sciences Gabriel, Université de Bourgogne, 6 Boulevard Gabriel, 21100 Dijon, France
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29
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Monovalent copper as a potential catalyst for formation of acetaldehyde via the migration of methyl radicals to the coordinated carbonyl in the complex (CO)CuII-CH3+. Inorganica Chim Acta 1998. [DOI: 10.1016/s0020-1693(97)06001-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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30
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Müh U, Buckel W, Bill E. Mössbauer study of 4-hydroxybutyryl-CoA dehydratase--probing the role of an iron-sulfur cluster in an overall non-redox reaction. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 248:380-4. [PMID: 9346292 DOI: 10.1111/j.1432-1033.1997.t01-1-00380.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
4-Hydroxybutyryl-CoA dehydratase from Clostridium aminobutyricum catalyzes the dehydration of 4-hydroxybutyryl-CoA to crotonyl-CoA. Although dehydration is an overall non-redox reaction, the enzyme contains FAD and Fe-S clusters. Previous work has shown that the Fe-S clusters are difficult to reduce and therefore unlikely to be redox-active in catalysis. Here, Mössbauer spectroscopy has been used to characterise the Fe-S clusters in active as well as in air-inactivated enzyme. In zero magnetic field at 80 K and 4.2 K, the spectra of active dehydratase consisted mainly of one species (95%) with quadrupole splitting, deltaE(Q) = 1.00 mm s(-1) and isomer shift, delta = 0.43 mm s(-1). Magnetically perturbed Mössbauer spectra indicated a spin of zero. In the presence of 6 mM crotonyl-CoA, the spectra remained unchanged. Taken together, the data show that there are [4Fe-4S]2+ in the enzyme, most probably two clusters/homotetramer, that the four iron atoms in each cluster are coordinated in an identical fashion, and that there is no direct interaction with substrates. We therefore infer that the Fe-S clusters serve a structural rather than a catalytic role in 4-hydroxybutyryl-CoA dehydratase. In air-inactivated enzyme (10% residual activity), a new doublet appeared (58%) with deltaE(Q) = 0.72 mm s(-1), delta = 0.32 mm s(-1) and S = 0. The assignment of this subspectrum to [3Fe-4S]+ clusters, based on the typical Mössbauer parameters, is contradicted by the finding of spin zero for the species. One possible explanation could be spin-coupling of two [3Fe-4S]+ clusters in close proximity.
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Affiliation(s)
- U Müh
- Laboratorium für Mikrobiologie am Fachbereich der Philipps Universität Marburg, Germany
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31
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George P, Glusker JP, Bock CW. An ab Initio Computational Molecular Orbital Study of Radical, Protonated Radical (Radical Cation), and Carbocation Species That Have Been Proposed in Mechanisms for the Transfer Process in the Enzyme−Coenzyme B12-Catalyzed Dehydration of 1,2-Dihydroxyethane. J Am Chem Soc 1997. [DOI: 10.1021/ja963424v] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Philip George
- Contribution from The Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, the Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and the Department of Chemistry, Philadelphia College of Textiles and Science, Philadelphia, Pennsylvania 19144
| | - Jenny P. Glusker
- Contribution from The Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, the Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and the Department of Chemistry, Philadelphia College of Textiles and Science, Philadelphia, Pennsylvania 19144
| | - Charles W. Bock
- Contribution from The Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, the Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and the Department of Chemistry, Philadelphia College of Textiles and Science, Philadelphia, Pennsylvania 19144
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32
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Goldstein S, Meyerstein D, Czapski G. Mechanisms of Reactions of (*)NO with Complexes with Metal-Carbon sigma-Bonds and with Aliphatic Radicals. Inorg Chem 1997; 36:2893-2897. [PMID: 11669928 DOI: 10.1021/ic9614327] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The competition kinetics between metal complexes and (*)NO for aliphatic radicals is a convenient technique for determining the rate constants of the reactions of (*)NO with aliphatic radicals. Thus, the rate constants of (*)CH(3) and (*)CH(2)OH with (*)NO were determined to be (3.4 +/- 1.1) x 10(9) and (5.9 +/- 0.5) x 10(9) M(-)(1) s(-)(1), respectively. The same rate constants can be determined, in several systems, from the decrease in the half-life of transient complexes with metal-carbon sigma-bonds which decompose homolytically. In the presence of (*)NO, the half-life of these transient complexes decreases, and their decomposition turns from second-order to first-order processes. From the dependence of the observed first-order rate constant on (*)NO and on the metal complex concentrations, it is concluded that the mechanism of the decomposition of these transients in the presence of (*)NO involves the reaction of (*)NO with the carbon-centered radicals as well as with the transient with the metal-carbon sigma-bonds to form the same products. The rate constants of the reactions of (*)NO with (cyclam)(H(2)O)Ni(III)CH(3)(2+) and (nta)Co(III)CH(2)OH(H(2)O)(-) were determined to be (1.5 +/- 0.2) x 10(5) and (3.6 +/- 0.4) x 10(8) M(-)(1) s(-)(1), respectively. The reactions of (*)NO with complexes with metal-carbon sigma-bonds are analogous to those of aliphatic radicals and dioxygen with the same complexes. This is not surprising as (*)NO is a radical. The biological implications of these results are discussed.
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Affiliation(s)
- Sara Goldstein
- Department of Physical Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel, and Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, and The College of Judea and Samaria, Kdumim-Ariel, Israel
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33
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The hydrogen-bridged radical cation [H2O⋯H⋯OCOH·+: A combined experimental and theoretical study of its stability and dissociation chemistry. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s0168-1176(96)04496-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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34
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Darbre T, Keese R, Siljegovic V, Wolleb-Gygi A. Model Studies for the Coenzyme-B12-Catalyzed Methylmalonyl?Succinyl Rearrangement. The Importance of Hydrophobic Peripheral Associations. Helv Chim Acta 1996. [DOI: 10.1002/hlca.19960790807] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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35
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Speranza G, Manitto P, Fontana G, Monti D, Galli A. Evidence for enantiomorphic-enantiotopic group discrimination in diol dehydratase-catalyzed dehydration of meso-2,3-butanediol. Tetrahedron Lett 1996. [DOI: 10.1016/0040-4039(96)00808-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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36
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Affiliation(s)
- Yukito Murakami
- Department of Chemical Science and Technology, Faculty of Engineering, Kyushu University and Institute for Fundamental Research in Organic Chemistry, Kyushu University, Fukuoka 812-81, Japan
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37
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Synthesis and characterization of coenzyme B12 base-off form analogs— 2′-deoxynucleosidylcobinamides. J Inorg Biochem 1996. [DOI: 10.1016/0162-0134(95)00030-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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38
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Structural behaviour of cobaloximes: planarity, an anomalous trans-influence and possible implications on CoC bond cleavage in coenzyme-B12-dependent enzymes. J Mol Struct 1996. [DOI: 10.1016/0022-2860(95)09034-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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39
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Luo LB, Chen HL, Tang WX, Zhang ZY, Mak TCW. Formation and structure of inclusion complexes involving α-cyclodextrin and alkyl(aqua)cobaloxime. ACTA ACUST UNITED AC 1996. [DOI: 10.1039/dt9960004425] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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40
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Structural behaviour of cobaloximes: planarity, an anomalous trans-influence and possible implications on Co-C bond cleavage in coenzyme-B12-dependent enzymes. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s0166-1280(96)80064-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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41
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Yan H, Chen H, Qian Y, Tang W. The first study on 2′,5′-dideoxynucleosidyl radicals formed from the anaerobic photolysis of 2′,5′-dideoxynucleosidylcobalamins by the ESR spin-trapping technique. J Inorg Biochem 1994. [DOI: 10.1016/0162-0134(94)85106-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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42
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Murakami Y, Hisaeda Y, Kohno H, Ohno T, Nishioka T. Hydrophobic Vitamin B12. XI. Preparation, Characterization, and Enantioselective Alkylation of Hydrophobic Vitamin B12Bearing a Binaphthyl Moiety. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1992. [DOI: 10.1246/bcsj.65.3094] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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43
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Alkylcobalamins: Formation by enantioselective alkylation of cob(I)alamin, 1H NMR spectra, and conformational analysis of the alkyl group. J Organomet Chem 1992. [DOI: 10.1016/0022-328x(92)83446-o] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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44
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Abstract
Developing artificial holoenzymes requires attention to the molecular design, not only of the active site, but also of its microenvironment, which in the naturally occurring enzyme is provided by the apoprotein. Microenvironmental effects play a major role in determining the catalytic performance of an enzyme. Using the development of a B12-dependent holoenzyme mimetic as an example, the important factors and concepts underlying the approaches to developing an artificial holoenzyme are discussed.
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Affiliation(s)
- Y Murakami
- Department of Organic Synthesis, Faculty of Engineering, Kyushu University, Fukuoka, Japan
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45
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van Eldik R, Cohen H, Meyerstein D. Druckunterstützte Knüpfung einer Co-C-σ-Bindung; eine Pulsradiolyse-Untersuchung unter hohem Druck. Angew Chem Int Ed Engl 1991. [DOI: 10.1002/ange.19911030930] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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46
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Murakami Y, Hisaeda Y, Song XM, Fan SD, Ohno T. Catalytic Functions of Artificial Enzyme Composed of Simple Vitamin B12Model and Synthetic Bilayer Membrane. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1991. [DOI: 10.1246/bcsj.64.2744] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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47
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Ryabov AD. Wechselwirkungen und Reaktionen von Organometallverbindungen mit Enzymen und Proteinen. Angew Chem Int Ed Engl 1991. [DOI: 10.1002/ange.19911030806] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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48
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van Arkel B, van der Baan JL, Balt S, Bickelhaupt F, de Bolster MWG, Kingma IE, Klumpp GW, Moos JWE, Spek AL. A new model for coenzyme B12with an intramolecular cobalt–carbon bridge. ACTA ACUST UNITED AC 1991. [DOI: 10.1039/c39910000225] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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49
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Geremia S, Mari M, Randaccio L, Zangrando E. Evidence of steric influences on the CoC bond lengths in vitamin B12 model compounds. J Organomet Chem 1991. [DOI: 10.1016/0022-328x(91)80103-q] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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50
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Shepherd RE, Songsheng Z, Dowd P, Choi G, Wilk B, Soo-Chang C. One-electron reduction potentials of coenzyme B12 and alkylcobalamins. Inorganica Chim Acta 1990. [DOI: 10.1016/s0020-1693(00)80308-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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