Short communication, Note
Experimental and Modelling Study of Enzymatic Oxidation of 5-o-Caffeoylquinic Acid by Polyphenol Oxidases
Tarcila Bueno dos Santos
; Federal University of Paraná, Polytechnic Center (DTQ/ST/UFPR), Graduate School of Chemical Engineering, Jardim das Américas, 81531-990, Curitiba, PR, Brazil
David Alexander Mitchell
; Federal University of Paraná, Polytechnic Center (DTQ/ST/UFPR), Graduate School of Chemical Engineering, Jardim das Américas, 81531-990, Curitiba, PR, Brazil
Nadia Krieger
; Federal University of Paraná, Polytechnic Center (DTQ/ST/UFPR), Department of Chemistry, Jardim das Américas, 81531-990, Curitiba, PR, Brazil
Vivian Rotuno Moure
; Federal University of Paraná, Polytechnic Center (DTQ/ST/UFPR), Department of Chemistry, Jardim das Américas, 81531-990, Curitiba, PR, Brazil
Éverton Fernando Zanoelo
; Federal University of Paraná, Polytechnic Center (DTQ/ST/UFPR), Graduate School of Chemical Engineering, Jardim das Américas, 81531-990, Curitiba, PR, Brazil
Abstract
A set of experiments to investigate the enzymatic oxidation of 5-o-caffeoylquinic acid with polyphenol oxidases was carried out in the temperature range from 18 to 39 °C. The kinetic data were obtained in a batch isothermal reactor made of quartz and operated at an optimum pH (approx. 7.0) for enzyme activity, using citrate-phosphate buffer. The decay of 5-o-caffeoylquinic acid concentrations was experimentally monitored with a spectrophotometer at 323 nm. A coefficient of molar absorptivity equal to 1.96·103 mM–1m–1 was found for 5-o-caffeoylquinic acid, based on absorbance measurements with standard aqueous solutions. The kinetic experimental results were used to calculate the parameters Km and vmax of the Michaelis-Menten model, which were 0.24 mM and 2.77·10–4 mM/s at 25 °C, respectively. The effects of temperature on the maximum velocity of oxidation of 5-o-caffeoylquinic acid and on the rate of enzyme deactivation were well described using the Arrhenius equation.
Keywords
chlorogenic acids; 5-CQA; enzymatic oxidation; polyphenol oxidases
Hrčak ID:
61727
URI
Publication date:
15.12.2010.
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