Abstract
Abstract: Inhibition-based biosensors were developed by immobilizing tyrosinase (Tyr, polyphenol oxidase) from the crude extract of avocado fruit on electrochemically prepared polypyrrole (PPy) films. The biosensors were prepared during the electropolymerization of pyrrole in a solution containing a fixed volume of the crude extract of avocado. The dependence of the biosensor responses on the volume used from the crude extract, values of pH and temperature was studied, and a substrate, catechol, at different concentrations, was amperometrically detected by these biosensors. Benzoic acid, a competitive inhibitor of Try, was added to the catechol solutions at specific concentrations aimed at obtaining the inhibition constant, K’ m , which ranged from 1.7 to 4.6 mmol∙L −1 for 0.0 and 60 µmol∙L −1 of benzoic acid, respectively. Studies on the inhibition caused by benzoic acid by using PPy/Try films, and catechol as a substrate, allowed us propose how to develop, under optimized conditions, simple and low-cost biosensors based on the use of avocado fruit.
Highlights
Biosensors based on the immobilization of enzymes within polymer matrices are considered to be a promising technology for detection of species of interest [1]
Amperometric biosensors have been reported in the monitoring of benzoic acid due to such advantages as effectiveness, simplicity, and low cost [8,9]
A systematic evaluation of the inhibition effects of PPy/Tyr films in the presence of benzoic acid has indicated that optimized conditions yield efficient, simple, and low-cost biosensors by using crude extract of avocado fruit as an enzymatic source
Summary
Biosensors based on the immobilization of enzymes within polymer matrices are considered to be a promising technology for detection of species of interest [1]. The mechanisms of enzyme inhibition are often complex, and can be studied by exposing an immobilized enzyme to a specific inhibitor and, interfering with the active sites of the enzyme to either retard or accelerate reaction rates. These mechanisms can be classified into different types: reversible, irreversible or mixed, and the main difference between them is that irreversible enzyme–inhibitor interactions yield hydrolytic and oxidative destruction of the enzyme [3]. A systematic evaluation of the inhibition effects of PPy/Tyr films in the presence of benzoic acid has indicated that optimized conditions yield efficient, simple, and low-cost biosensors by using crude extract of avocado fruit as an enzymatic source
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
