CHEMILUMINESCENCE-BASED INHIBITION-KINETICS OF ALKALINE-PHOSPHATASE IN THE DEVELOPMENT OF A PESTICIDE BIOSENSOR

The use and application of the enzyme alkaline phosphatase in a chemil uminescence assay are discussed. The enzyme catalyzes the hydrolysis o f a macrocyclic phosphate compound generating a chemiluminescence sign al. On the basis of inhibition of this signal, a methodology for the d etection and quantitation of organophosphorus-based pesticides has bee n developed. The methodology is studied with alkaline phosphatase in t he bulk aqueous phase, and detection of the signal is accomplished by a simple optical setup. Parts per billion level detection of paraoxon and methyl parathion in bulk solutions is achieved. The technique is r apid and sensitive and is applicable to the detection of most organoph osphorus-based pesticides. The results from kinetic studies indicate a mixed type of inhibition of the enzyme by paraoxon and methyl parathi on. The detection methodology forms an integral part of a biosensor un der development and is adaptable to incorporating optical fibers for r emote detection of pesticides.