Immobilization of chemically modified horse radish peroxidase within activated alginate beads

Imobilizacija peroksidaze iz rena unutar alginatnih kuglica je poboljšana hemijskom modifikacijom enzima i polisaharidnih lanaca. Peroksidaza i alginat su oksidovani perjodatom i naknadno modifikovani etilendiaminom. Najveća specifična aktivnost od 0,43 U/ml gela i 81% vezane aktivnosti je dobijeno korišćenjem aminovane peroksidaze i alginata oksidovanog perjodatom. Imobilizovani enzim je zadržao 75% originalne aktivnosti nakon 2 dana inkubacije u 80% (v/v) dioksanu i imao je povećanu aktivnost pri baznim pH vrednostima u poređenju sa nativnim enzimom. Tokom višestruke upotrebe u šaržnom reaktoru za oksidaciju pirogalola imobilizovana peroksidaza je zadržala 75% početne aktivnosti.Immobilization of horseradish peroxidase (HRP) within alginate beads was enabled by chemical modification of the enzyme and polysaccharide chains. HRP and alginate were oxidized by periodate and subsequently modified with ethylenediamine. Highest specific activity of 0.43 U/ml of gel and 81% of bound enzyme activity was obtained using aminated HRP and alginate oxidized by periodate. Immobilized enzyme retained 75% of its original activity after 2 days of incubation in 80% (v/v) dioxane and had increased activity in basic solutions compared to native enzyme. During repeated use in batch reactor for pyrogallol oxidation immobilized peroxidase retained 75% of its original activity

Effect of phenol on germination capacity and polyphenol oxidase, peroxidase and catalase activities in lettuce

In this study we examined the activities of polyphenol oxidase (PPO) and antioxidant enzymes, peroxidase (POX) and catalase (CAT) during lettuce seed germination at different concentrations of phenol. Out of eleven varieties of lettuce, four were chosen according to their germination tolerance to phenol as follows: plants exhibiting high (Ljubljanska ledenka - LJL and Nansen - N) and low toleranace (Little Gem - LG and Majska kraljica - MK). A decrease in germination efficiency after exposure to LD50 of phenol was determined for these four varieties. The effects of phenol treatment on POX, CAT and PPO activities were determined after 4, 5, 6, 7 and 8 days of growth at LD50 concentrations. A trend of increased peroxidase activity was observed in seeds grown on LD50 of phenol compared to control seeds. A significant increase in CAT activity was observed at the beginning of treatment for MK, LG and N in seeds grown on phenol as well as in control seeds. A trend of increased PPO activity was observed in all control seeds. We also investigated the affinity of PPO for two different substrates that were used for the determination of enzyme activity. Our results show that LJL and N are the varieties most tolerant to growth on phenol. Here we report on the activities of their antioxidant enzymes and PPO during seed germination.Serbian Ministry of Education, Science and Technological Development {[}ON173017