Mechanism of the oxidation of sulphides with sodium periodate

Ruff, F.; Kucsman, Árpád

doi:10.1039/p29850000683

Cited by 85 publications

(91 citation statements)

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“…1). Hammett o-p values, solvent isotope effects, and pHdependence studies (11,12) M-1s-1), similar to the flavin-dependent enzymes (7). To determine the catalytic mechanism of 28B4 and the extent to which the active site evolved in response to mechanistic instructions from the hapten, the free and hapten-bound structures of the antigen-binding fragment (Fab) of the murine antibody 28B4 have been solved to 2.2-A and 1.9-A resolution, respectively.…”

Section: Introductionmentioning

confidence: 99%

Insights into antibody catalysis: structure of an oxygenation catalyst at 1.9-angstrom resolution.

Hsieh‐Wilson

Schultz

Stevens

1996

Proc. Natl. Acad. Sci. U.S.A.

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The x-ray crystal structures of the sulfide oxidase antibody 28B4 and of antibody 28B4 complexed with hapten have been solved at 2.2-A and 1.9-A resolution, respec-tively. To our knowledge, these structures are the highest resolution catalytic antibody structures to date and provide insight into the molecular mechanism of this antibodycatalyzed monooxygenation reaction. Specifically, the data suggest that entropic restriction plays a fundamental role in catalysis through the precise alignment of the thioether substrate and oxidant. The antibody active site also stabilizes developing charge on both sulfur and periodate in the transition state via cation-pi and electrostatic interactions, respectively. In addition to demonstrating that the active site of antibody 28B4 does indeed reflect the mechanistic information programmed in the aminophosphonic acid hapten, these high-resolution structures provide a basis for enhancing turnover rates through mutagenesis and improved hapten design.Antibodies have been shown to catalyze a wide variety of reactions with exquisite control over the reaction pathway (1). However, the further improvement of antibody catalysis depends on high-resolution structural data. The few reported crystal structures of catalytic antibodies have focused, with one exception, on esterolytic reactions (2-6). We now report the three-dimensional structure of an antibody (28B4) that catalyzes the monooxygenation of thioethers. An examination of the structural data may provide insight into enhancing the catalytic efficiencies of antibodies as well as elucidate the mechanisms and evolution of enzymatic catalysis.Antibody 28B4 catalyzes the periodate-dependent oxidation ( Fig. 1) of sulfide 1 to the corresponding sulfoxide 2 (7). Similar oxygen transfer reactions are performed by naturally occurring monooxygenase enzymes for the biosynthesis of steroids and neurotransmitters, the degradation of endogenous substances, and the detoxification of xenobiotics (8, 9). This reaction was initially examined to extend antibody catalysis to this important class of redox reactions and (ii) to expand the range of "cofactors" used in biological catalysis. The combination of highly abundant and versatile chemical reagents such as metal hydrides and Lewis acids together with antibody catalysis might lead to a number of advantages over natural enzymes, such as eliminating the need for expensive cofactor recycling in large-scale enzymatic synthesis (10).The periodate-dependent oxygenation of thioethers can occur either via sulfur attack on the periodate oxygen in a concerted, SN2-like transition state (TS*) or by initial addition to the iodine center followed by oxygen transfer (Fig. 1) Eight antibodies were found to catalyze the oxidation of substrate 1 and related sulfides with a range of turnover numbers and stereoselectivities. Antibody 28B4, which was among the most efficient, binds hapten 3 with high affinity (Kd= 52 nM) and catalyzes the periodate-dependent oxidation of sulfide 1 with a kcat value of 8.2 s-1...

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Section: Introductionmentioning

confidence: 99%

Insights into antibody catalysis: structure of an oxygenation catalyst at 1.9-angstrom resolution.

Hsieh‐Wilson

Schultz

Stevens

1996

Proc. Natl. Acad. Sci. U.S.A.

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“…7,8 An increase in solvent polarity sharply increases reaction rates, as also seems to be general for oxygen transfers.…”

Section: Introductionmentioning

confidence: 93%

Effect of sulfuric acid on reactions of peroxymonosulfate ion with sulfides and thiol esters

Bunton

Kumar

1998

J. Phys. Org. Chem.

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“…The reaction constants and statistical data for different temperatures are recorded in Table VI. The magnitudes of p I and p R for both meta-and para-compounds are small and negative supporting the involvement of direct oxygen transfer via an electrophilic attack on the sulphur atom [20]. In oxidation by reagents which involve electrophilic attack on sulphur atom, the reaction constants are negative and of smaller magnitudes [19 -22].…”

Section: Correlation Analysis Of Reactivitymentioning

confidence: 99%

Oxidative cleavage of S-Arylmercaptoacetic acids by pyridinium chlorochromate: Kinetic and correlation analysis

Kabilan

Girija

Rajagopal

1999

Int. J. Chem. Kinet.

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Kinetics of oxidation of 24 S-Arylmercaptoacetic acids (SAMA) by pyridinium chlorochromate (PCC) have been studied in acidmedium. The product of oxidation is the corresponding thiophenol. The rate data of meta-and para-substituted acids have been correlated well with I , R o values and the meta-compounds correlate well with F,R values. The reaction constants are negative and of smaller magnitudes. Further, the ortho-substituted acids show a good correlation with triparametric equation involving Taft's I and R o and charton's steric parameter v. There is no considerable steric contribution to the total orthosubstituent effect. Based on these observations, the mechanism involving the formation of protonated arylsulfinylacetic acid intermediate, followed by an intramolecular rearrangement leading to the product thiophenol has been proposed.

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Mechanism of the oxidation of sulphides with sodium periodate

Cited by 85 publications

References 0 publications

Insights into antibody catalysis: structure of an oxygenation catalyst at 1.9-angstrom resolution.

Insights into antibody catalysis: structure of an oxygenation catalyst at 1.9-angstrom resolution.

Effect of sulfuric acid on reactions of peroxymonosulfate ion with sulfides and thiol esters

Oxidative cleavage of S-Arylmercaptoacetic acids by pyridinium chlorochromate: Kinetic and correlation analysis

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