KINETIC PROPERTIES OF BUTYRYLCHOLINESTERASES IMMOBILISED ON pH-SENSITIVE FIELD-EFFECT
TRANSISTOR SURFACE AND INHIBITORY ACTION OF STEROIDAL GLYCOALKALOIDS ON THESE ENZYMES
1Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kyiv;
2Ecole Centrale de Lyon, Ecully Cedex, France;
The inhibitory action of steroid glycoalkaloids ?-solanine, ?-chaconine and tomatine on horse and human serum butyryl cholinesterases immobilized on the pH-sensitive field-effect transistors has been studied. Using acetyl- and butyryl choline as substrates, the optimal pH and the apparent kinetic parameters (<Km>, <Vmax>) of immobilized butyryl cholinesterases have been calculated in the absence of inhibitors. The affinity of each enzyme to glycoalkaloids has been estimated from calculation of apparent inhibition constants <Ki> and inhibition coefficients i0.5. Application of the studied cholinesterases for biosensoric determination of glycoalkaloids in the wide range of concentrations (10-7–10-4 M) in different media has been discussed.
Key words: immobilized cholinesterases, potentiometric biosensor, glycoalkaloids, reversible inhibitors, kinetic constants, affinity.
Published at the site: 2006-09-18
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© The Ukrainian Biochemical Journal