Pyridoxal 5′-Phosphate-dependent Catalytic Antibody
Cofactors might efficiently extend the catalytic potential of antibodies. Monoclonal antibodies against Nα-phosphopyridoxyl-L-lysine were screened for: 1) binding of 5′-phosphopyridoxyl amino acids, 2) binding of Schiff base of pyridoxal 5′-phosphate (PLP) and amino acids, the first intermediate of...
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Veröffentlicht in: | The Journal of biological chemistry 1996-11, Vol.271 (48), p.30583-30586 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Cofactors might efficiently extend the catalytic potential of antibodies. Monoclonal antibodies against Nα-phosphopyridoxyl-L-lysine were screened for: 1) binding of 5′-phosphopyridoxyl amino acids, 2) binding of Schiff base of pyridoxal 5′-phosphate (PLP) and amino acids, the first intermediate of all PLP-dependent reactions, and 3) catalysis of PLP-dependent α,β-elimination with β-chloro-D/L-alanine. All three criteria were met by antibody 15A9. Further analysis for PLP-dependent reactions showed that this antibody catalyzes the cofactor-dependent transamination of hydrophobic D-amino acids and oxo acids (kcat′ = 0.42 min−1 with D-alanine). No other reactions with either D- or L-amino acids were taking place. PLP markedly contributes to catalytic efficacy, being a 104 times more efficient acceptor of the amino group than pyruvate. The antibody further accelerates the reaction (kcat(antibody)′/kcat(PLP)′ = 5 × 103 with D-alanine as substrate) and ensures reaction specificity, stereospecificity, as well as limited substrate specificity. |
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ISSN: | 0021-9258 1083-351X |
DOI: | 10.1074/jbc.271.48.30583 |