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Catalytic Antibodies Induced by a Zwitterionic Hapten
Author(s) -
Tsumuraya Takeshi,
Takazawa Nobuo,
Tsunakawa Atsuko,
Fleck Roman,
Masamune Satoru
Publication year - 2001
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20010903)7:17<3748::aid-chem3748>3.0.co;2-g
Subject(s) - hapten , enzyme kinetics , catalysis , hydrolysis , chemistry , kinetics , reaction rate constant , amide , bovine serum albumin , heterologous , michaelis–menten kinetics , antibody , stereochemistry , medicinal chemistry , enzyme , biochemistry , biology , active site , enzyme assay , physics , quantum mechanics , gene , immunology
A zwitterionic hapten 4 featuring both positively and negatively charged functional groups was designed and synthesized with the goal of generating catalytic antibodies for the hydrolysis of ester 6 and amide 7 . Of the 36 monoclonal antibodies specific to BSA– 4 (bovine serum albumin) that were isolated, six accelerated the hydrolysis of 6 . Two catalytic antibodies with distinctively different and representative kinetic behaviors were selected for detailed kinetic studies. Whereas H8‐2‐6F11 showed burst kinetic behavior, which can be attributed to the formation of an acyl intermediate, H8‐1‐2D5 did not, but it did exhibit high multiple turnover activity. The rate of hydrolysis of 6 catalyzed by H8‐1‐2D5 followed Michaelis–Menten kinetics; the apparent values of the Michaelis–Menten constant K m and the catalytic constant k cat were 488 μ M and 3.5 min −1 , respectively. The catalytic rate enhancement ( k cat / k un ) observed for H8‐1‐2D5 was 1.3×10 5 , which is approximately two orders of magnitude greater than those for monofunctional haptens. Thus H8‐1‐2D5 compares well in catalytic activity with antibodies isolated by a related approach called heterologous immunization.