An Efficient Antibody-Catalyzed Aminoacylation Reaction
Autor: | Shirlee Yonkovich, John R. Jacobsen, James R. Prudent, Lynn Kochersperger, Peter G. Schultz |
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Rok vydání: | 1992 |
Předmět: |
Alanine
Multidisciplinary Esterification Stereochemistry Acylation Kinetics Organophosphonates Antibodies Monoclonal Serum Albumin Bovine Aminoacylation Phosphonate Catalysis Amino Acyl-tRNA Synthetases Dissociation constant chemistry.chemical_compound Reaction rate constant chemistry Hemocyanins Thymidine Haptens Hapten Chromatography High Pressure Liquid |
Zdroj: | Science. 256:365-367 |
ISSN: | 1095-9203 0036-8075 |
DOI: | 10.1126/science.256.5055.365 |
Popis: | An antibody generated against a neutral phosphonate diester transition-state analog was found to catalyze the aminoacylation of the 3'-hydroxyl group of thymidine with an alanyl ester. A comparison of the apparent second-order rate constant of the antibody-catalyzed reaction [5.4 x 10(4) molar-1 minute-1 (M-1 min-1)] with that of the uncatalyzed reaction (2.6 x 10(-4) M-1 min-1) revealed this to be a remarkably efficient catalyst. Moreover, although the concentration of water (55 M) greatly exceeds that of the secondary alcohol, the antibody selectively catalyzes acyl transfer to thymidine. The antibody exhibits sequential binding, with Michaelis constants of 770 microM and 260 microM for acyl acceptor and donor, respectively, and a dissociation constant of 240 pM for hapten. This antibody-catalyzed reaction provides increased insight into the requirements for efficient aminoacylation catalysts and may represent a first step toward the generation of "aminoacyl transfer RNA synthetases" with novel specificities. |
Databáze: | OpenAIRE |
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