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Journal of Tea Science ›› 2015, Vol. 35 ›› Issue (1): 17-23.doi: 10.13305/j.cnki.jts.2015.01.004

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The Cloning and Prokaryotic Expression of Polyphenol Oxidase Gene in Pear (Pyrus Pyrifolia Nakai)

CHEN Dongsheng, WANG Kunbo*, LI Qin, LI Juan, HUANG Jian′an, LIU Zhonghua*   

  1. National Research Center of Engineering & Technology for Utilization of Botanical Functional Ingredients, Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha 410128, China
  • Received:2014-06-04 Revised:2014-09-29 Published:2019-08-23

Abstract: :The polyphenol oxidase (PPO, GenBank accession No. JQ861265) genes were cloned by PCR from Pyrus Pyrifolia Nakai. The full length of PPO gene was 1β782βbp without introns, coding a precursor peptide. PPO precursor consists of 593 amino acids with a molecular weight of about 65.8βkDa. It has a theoretical PI of 8.4 and has a transit peptide consisting of 47 amino acids. The mature PPO without transit peptide consists of 547 amino acids with a molecular weight of about 60.8βkDa and a theoretical PI of 6.69. There are 2 Cu-binding domain in the α-helix of PPOs. The protein accumulation got a peak in 3-6 hours. The induced proteins (precursor PPO and mature PPO) can oxidize catechins into theaflavins in vitro.

Key words: polyphenol oxidase, gene clone, prokaryotic expression, enzymatic synthesis, theaflavins

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