Related Experiment Video
Updated: Aug 23, 2026

Fabrication of Electrochemical-DNA Biosensors for the Reagentless Detection of Nucleic Acids, Proteins and Small Molecules
Published on: June 1, 2011
Molecular recognition of cocaine by acetylcholinesterases for affinity purification and bio-sensing
Kristina Knösche1, Jan Halámek, Alexander Makower
1Department of Analytical Biochemistry, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Golm, Germany. knoesche@rz.uni-potsdam.de
Abstract:
Cholinesterases can be used as sensitive biorecognition elements for widely used agricultural pesticides. This requires highly purified and inhibitor-free enzyme preparations. In the present work the cocaine derivative benzoylecgonine was for the first time used as the molecular recognition element for the purification of acetylcholinesterase from Electrophorus electricus by affinity chromatography. The preparation of enriched enzyme without the contamination by an inhibitor, which is traditionally used for eluting the "affinity" bound protein, was achieved. The specific activity was 2.2-fold increased to 3100 Umg(-1). The same cocaine derivative was immobilized on the surface of a piezoelectric crystal in order to analyze the binding of acetylcholinesterases from two different species, E. electricus and Drosophila melanogaster, to the immobilized inhibitor. Evaluation of the binding curves allowed the analysis of the binding kinetics. These experiments are fundamental for the development of a (competitive) biosensor for inhibitors of cholinesterase.
Related Concept Videos
Direct-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
The direct-acting...
Direct-Acting Cholinergic Agonists: Pharmacokinetics
Indirect-Acting Cholinergic Agonists: Mechanism of Action
Reversible inhibitors like edrophonium bind to a specific part of the enzyme called the anionic catalytic site. They form noncovalent bonds, which means they are not strongly attached to the enzyme. This creates a temporary and less stable enzyme–inhibitor complex, leading to...
Indirect-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
Reversible inhibitors display short to medium durations of action. Short-acting agents include simple alcohols with...
Cholinergic Receptors: Muscarinic
The subtypes M1, M3, and M5 couple with the Gq subunit and activate the phospholipase C (PLC) activity, mobilizing intracellular Ca2+. Activation...
Affinity Chromatography
