An investigation of antibody acyl hydrolysis catalysis using a large set of related haptens

Odenbaugh, Amy L.; Helms, Eric D.; Iverson, Brent L.

doi:10.1016/s0968-0896(99)00302-8

Cited by 7 publications

(9 citation statements)

References 25 publications

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“…[1][2][3]). This made possible systematic study of the relationship between haptenic structure and antibody recognition and catalytic activity (see [4] and the first 21 references cited therein). The development of the polyclonal catalytic antibody field (reviewed recently in [5]) followed earlier successes reported with monoclonal catalytic antibodies (initially reported in [6,7]; reviewed in e.g.…”

Section: Improvement In Hydrolytic Antibody Activity By Change In Hapmentioning

confidence: 99%

“…Both anxieties have been shown to be without foundation. Thus, as far as the first is concerned, catalysis by all of the polyclonal IgG preparations investigated to date in different laboratories has not deviated from single-site (Michaelis-Menten) saturation kinetics (e.g [2][3][4][10][11][12][13][14][15][16][17][18]). Given the heterogeneous nature of the polyclonal antisera, this observation may be regarded as counter-intuitive.…”

Section: Improvement In Hydrolytic Antibody Activity By Change In Hapmentioning

confidence: 99%

“…Recent work by Iverson's group has begun to address the important question of the relationship between haptenic structure and the resulting success or otherwise in eliciting antibody catalysts, given a high-affinity immune response. A paper [4] describes an investigation of the effects of small modifications in haptens on the resultant catalytic antibody activity. The hydrolysis of six isomeric benzyl ester or benzyl carbonate substrates was not catalysed by polyclonal antibodies generated by six congruent benzyloxy phosphorus transition-state analogues.…”

Section: Improvement In Hydrolytic Antibody Activity By Change In Hapmentioning

confidence: 99%

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Improvement in hydrolytic antibody activity by change in haptenic structure from phosphate to phosphonate with retention of a common leaving-group determinant: evidence for the ‘flexibility’ hypothesis

Gul

Sonkaria

Pinitglang

et al. 2003

Biochemical Journal

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To investigate the hypothesis that decreased hapten flexibility may lead to increased catalytic antibody activity, we used two closely related immunogens differing only in the flexibility of the atomic framework around the structural motif of the haptens, analogous to the reaction centre of the corresponding substrates. Identical leaving-group determinants in the haptens and identical leaving groups in the substrates removed the ambiguity inherent in some data reported in the literature. Anti-phosphate and anti-phosphonate kinetically homogeneous polyclonal catalytic antibody preparations were compared by using carbonate and ester substrates respectively, each containing a 4-nitrophenolate leaving group. Synthetic routes to a new phosphonate hapten and new ester substrate were developed. The kinetic advantage of the more rigid anti-phosphonate/ester system was demonstrated at pH 8.0 by a 13-fold advantage in k(cat)/k(non-cat) and a 100-fold advantage in the proficiency constant, k(cat)/k (non-cat) x K(m). Despite these differences, the pH-dependences of the kinetic and binding characteristics and the results of chemical modification studies suggest closely similar catalytic mechanisms. The possible origin of the kinetic advantage of the more rigid hapten/substrate system is discussed.

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Section: Improvement In Hydrolytic Antibody Activity By Change In Hapmentioning

confidence: 99%

Section: Improvement In Hydrolytic Antibody Activity By Change In Hapmentioning

confidence: 99%

Section: Improvement In Hydrolytic Antibody Activity By Change In Hapmentioning

confidence: 99%

See 1 more Smart Citation

Improvement in hydrolytic antibody activity by change in haptenic structure from phosphate to phosphonate with retention of a common leaving-group determinant: evidence for the ‘flexibility’ hypothesis

Gul

Sonkaria

Pinitglang

et al. 2003

Biochemical Journal

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“…It is important to emphasize that (i) polyclonal IgG preparations investigated to-date in different laboratories have not deviated from single-phase (Michaelis-Menten) saturation kinetics (e.g. see references cited in [19]), (ii) polyclonal preparations are free from contamination by enzymes, as shown in our laboratories by the use of isomeric substrates [7,20] and in other laboratories by the observation of catalysis of reactions for which there are no known enzymes [14,21], and (iii) the generation of PCAs by immunization with a transition-state analogue [7,[22][23][24] is a good way to sample the entirety of the immune response to the haptenic moiety of an immunogen. Catalysis of the hydrolysis of the substrate 5e (4-CH 3 O) was too weak to be quantified reliably when using the concentration of PCA 271-100 available.…”

Section: Kinetic Characteristicsmentioning

confidence: 99%

Evidence that the mechanism of antibody-catalysed hydrolysis of arylcarbamates can be determined by the structure of the immunogen used to elicit the catalytic antibody

Boucher

Said

Ostler

et al. 2007

Biochemical Journal

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A kinetically homogeneous anti-phosphate catalytic antibody preparation was shown to catalyse the hydrolysis of a series of O-aryl N-methyl carbamates containing various substituents in the 4-position of the O-phenyl group. The specific nature of the antibody catalysis was demonstrated by the adherence of these reactions to the Michaelis-Menten equation, the complete inhibition by a hapten analogue, and the failure of the antibody to catalyse the hydrolysis of the 2-nitrophenyl analogue of the 4-nitrophenylcarbamate substrate. Hammett sigma-rho analysis suggests that both the non-catalysed and antibody-catalysed reactions proceed by mechanisms in which development of the aryloxyanion of the leaving group is well advanced in the transition state of the rate-determining step. This is probably the ElcB (elimination-addition) mechanism for the non-catalysed reaction, but for the antibody-catalysed reaction might be either ElcB or B(Ac)2 (addition-elimination), in which the elimination of the aryloxy group from the tetrahedral intermediate has become rate-determining. This result provides evidence of the dominance of recognition of phenolate ion character in the phosphate hapten in the elicitation process, and is discussed in connection with data from the literature that suggest a B(Ac)2 mechanism, with rate-determining formation of the tetrahedral intermediate for the hydrolysis of carbamate substrates catalysed by an antibody elicited by a phosphonamidate hapten in which phenolate anion character is minimized. The present paper contributes to the growing awareness that small differences in the structure of haptens can produce large differences in catalytic characteristics.

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“…The hydrolysis of p-nitrophenyl acetate (NPA) was selected as the test reaction as it has a well-proven TSA (i.e. the p-nitrophenyl phosphate; NPP) for the transition state (scheme 1) [20,21]. Assembling with NPP as the template and 1-vinylimidazole as the functional monomer, the imprinted catalyst was prepared and used for substrate-discriminated hydrolysis.…”

Section: Introductionmentioning

confidence: 99%

Biomimic recognition and catalysis by an imprinted catalysts: a rational design of molecular self-assembly toward predetermined high specificity

Zhang

et al. 2007

Catal Lett

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This article presents an original work contributing to the rational design of imprinted catalyst by molecular self-assembly toward predetermined high specificity. Assembling with p-nitrophenyl phosphate as the transition state analogue (TSA) of pnitrophenyl acetate esterolysis and 1-vinylimidazole as the functional monomer, the imprinted catalyst was prepared. An increase in the amount of assembled monomer results in a higher activity of hydrolysis, which, however, does not lead to an improvement of specificity. The best specificity is shown at the optimal self-assembly (corresponding to a stoichiometric interaction of monomer-TSA). Higher or lower an amount of assembled monomer would lead to a dramatic decrease in this specificity. Related information indicates that these may be a result of increasing specific interaction between the TSA and binding sites, which make the catalyst capable of selectively recognizing the transition state and promoting the conversion from reactant to the transition state.

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An investigation of antibody acyl hydrolysis catalysis using a large set of related haptens

Cited by 7 publications

References 25 publications

Improvement in hydrolytic antibody activity by change in haptenic structure from phosphate to phosphonate with retention of a common leaving-group determinant: evidence for the ‘flexibility’ hypothesis

Improvement in hydrolytic antibody activity by change in haptenic structure from phosphate to phosphonate with retention of a common leaving-group determinant: evidence for the ‘flexibility’ hypothesis

Evidence that the mechanism of antibody-catalysed hydrolysis of arylcarbamates can be determined by the structure of the immunogen used to elicit the catalytic antibody

Biomimic recognition and catalysis by an imprinted catalysts: a rational design of molecular self-assembly toward predetermined high specificity

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