2018 Volume 39 Issue 1 Pages 33-39
Reversible inhibition of enzymes is caused by association and dissociation between enzymes and inhibitors. Therefore, reversible inhibitors can be trapped and extracted using enzyme-inhibitor interaction. The purpose of this study was to establish a method in which the reversible inhibitors retaining the original inhibitory activities are extracted from a single drop of biological sample using the enzyme-inhibitor interaction on the surface of a membrane. A membrane-immobilized carboxypeptidase Y (CPY) was produced after the biotinylated CPY was bound to the avidin separated by nondenaturing electrophoresis, transferred to a polyvinylidene fluoride and stained by Ponceau S. Ovomucoid, possessing reversible CPY inhibitory activity, was trapped and extracted from a single drop of egg white and isolated using the membrane-immobilized CPY. The isolated ovomucoid using this membrane-immobilized CPY possessed a feature that more than 85 % of the relative carboxylesterase activity was suppressed. The results indicate that ovomucoid retaining enzyme inhibitory activities can be isolated from a single drop of egg white sample using enzyme-immobilized membrane.