Recombinant polyphenol oxidases for production of theaflavins from tea polyphenols.

Recombinant polyphenol oxidases for production of theaflavins from tea polyphenols. Int J Biol Macromol. 2019 Apr 22;: Authors: Zeng J, Du G, Shao X, Feng KN, Zeng Y Abstract Theaflavins (TFs) have attracted much attention due to their various bioactivities in black tea. This paper describes the first trial for enzymatic production of TFs by recombinant polyphenol oxidases (PPOs). PPO genes were cloned from nine species and expressed in E. coli. Crude enzyme assays by LC-MS revealed that eight recombinant PPOs were active for TFs production from tea polyphenols as substrates. Much higher activities were observed for crude enzymes of Md2 from Malus domestica (apple), Pp4 from Pyrus pashia (pear), and Ej2 from Eriobotrya japonica (loquat). When immobilized on mesoporous silica, crude Md2 was most active. The purified Md2 was immobilized and showed almost twice activity as high as its free enzyme. While the maximum activity of free enzyme was found at pH 5 and 10-30 °C, the immobilized enzyme had broader range of pH 4-6 and 10-40 °C. The activity of immobilized enzyme was relatively constant during the pH and thermal stability test. When used at 0.2 mg/ml in the beginning, the immobilized enzyme retained approximately 40% of its initial activity after 8 cycles of operation. PMID: 31022487 [PubMed - as supplied by publisher]
Source: International Journal of Biological Macromolecules - Category: Biochemistry Authors: Tags: Int J Biol Macromol Source Type: research