“…The PPO showed the highest activity when pyrogallol was used as a substrate (100%), followed by 4-methyl catechol (67.44%), gallic acid (59.63%), catechol (33.71%), F I G U R E 2 Activity of POD and PPO as a function of substrate concentrations and Lineweaver-Burk plots using guaiacol as substrate for POD (a), H 2 O 2 substrate for POD (b), and pyrogallol for PPO (c) from pomegranate arils tyrosine (28.56%), and resorcinol (12.03%). PPO from various plant sources has been shown varying substrate specificity as reported in the literature (Aydemir, 2004;Dogan, Turan, Ertürk, & Arslan, 2005;McLarina & Leunga, 2020;Neves, Picchi, & Da Silva, 2009). POD reduces H 2 O 2 to water while oxidizing a variety of substrates (Nokthai, Lee, & Shank, 2010).…”