The metal effect on the Polyphenol oxidase enzyme from borage(Trachystemon orientalis) plant

In this study, Polyphenol oxidase was extracted from Borage plant (Trachystemon orientalis) and the crude extract was used for the assays. Its pH and temperature optima for 4-methyl cathecol were 5.0 and 5°C, respectively. Km of this enzyme was 4.55 mM for 4-methyl cathecol. We also found that the enzyme was activated by Fe3+, Mg2+, Zn2+, Cu2+, Ca2+, K+, but inhibited by Hg2+, Mn2+, Ni2+, Sn2+, Na+. Ba2+, Al3+ and Pb2+ metal ions both activated and inhibited the enzyme at different concentrations.