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## Abstract __In our search for a catalyst for the transamination reaction of aspartic acid to form oxaloacetate, twenty‐five forty‐two‐residue sequences were designed to fold into helix‐loop‐helix dimers and form binding sites for the key intermediate along the reaction pathway, the aldimine. This intermediate is formed from aspartic acid and the cofactor pyridoxal phosphate. The design of the binding sites followed a strategy in which exclusively noncovalent forces were used for binding the aldimine. Histidine residues were incorporated to catalyse the rate‐limiting 1,3 proton transfer reaction that converts the aldimine into the ketimine, an intermediate that is subsequently hydrolysed to form oxaloacetate and pyridoxamine phosphate. The two most efficient catalysts, T‐4 and T‐16, selected from the pool of sequences by a simple screening procedure, were shown by CD and NMR spectroscopies to bind the aldimine intermediate with dissociation constants in the millimolar range. The mean residue ellipticity of T‐4 in aqueous solution at pH 7.4 and a concentration of 0.75 mM was −18 500 deg cm__^__2__^__dmol__^__−1__^__. Upon addition of 6 mm l‐aspartic acid and 1.5 mM pyridoxal phosph

Author

Malin Allert; Lars Baltzer

Publisher

John Wiley and Sons; Wiley (John Wiley & Sons); John Wiley & Sons Ltd.; Wiley (ISSN 1439-4227)

Published

2003

Language

EN