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Purification and Characterization of a Dark Red Skin Related Dimeric Polyphenol Oxidase from Huaniu Apples
The distinct dark-red skin of Huaniu apples renders them attractive to customers. However, the mechanism that leads to the development of the color of the fruit is unclear. In this study, we found that compared with red Fuji (a bright-red apple cultivar), Huaniu apples had higher contents of (−)-epi...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9223062/ https://www.ncbi.nlm.nih.gov/pubmed/35741987 http://dx.doi.org/10.3390/foods11121790 |
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author | Liu, Bin Zhou, Xianfang Guan, Haiyan Pang, Xuequn Zhang, Zhaoqi |
author_facet | Liu, Bin Zhou, Xianfang Guan, Haiyan Pang, Xuequn Zhang, Zhaoqi |
author_sort | Liu, Bin |
collection | PubMed |
description | The distinct dark-red skin of Huaniu apples renders them attractive to customers. However, the mechanism that leads to the development of the color of the fruit is unclear. In this study, we found that compared with red Fuji (a bright-red apple cultivar), Huaniu apples had higher contents of (−)-epicatechin (EC), (−)-epigallocatechin (EGC), (−)-gallocatechin gallate (GCG), and procyanidins (PCs) B2 and C1 in the peel, which implies that the polymerization of the flavanols and PCs may be correlated with the dark-red skin of the fruit. Using EC as a substrate, we purified an enzyme from Huaniu peel. We performed protein sequencing and discovered that the enzyme was a polyphenol oxidase (PPO). The molecular weight of the enzyme was approximately 140 kDa, which we estimated by native-PAGE and SDS-PAGE, while it was 61 kDa by urea-SDS-PAGE, from which we discovered that the PPO was a dimer. We observed the lowest K(m) value for catechol (0.60 mM), and the best substrate was 4-methylcatechol, with a V(max) of 526.32 U mg(−1) protein. EC is a suitable natural substrate, with a K(m) value of 1.17 mM, and 55.27% of the V(max)/K(m) of 4-methylcatechol. When we used EC as a substrate, the optimum temperature and pH of the PPO were 25 °C and 5.0, respectively. In summary, we purified a dimeric PPO from Huaniu apples that showed high activity to EC, which might catalyze the polymerization of flavanols and PCs and lead to the dark-red color development of the fruit. |
format | Online Article Text |
id | pubmed-9223062 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-92230622022-06-24 Purification and Characterization of a Dark Red Skin Related Dimeric Polyphenol Oxidase from Huaniu Apples Liu, Bin Zhou, Xianfang Guan, Haiyan Pang, Xuequn Zhang, Zhaoqi Foods Article The distinct dark-red skin of Huaniu apples renders them attractive to customers. However, the mechanism that leads to the development of the color of the fruit is unclear. In this study, we found that compared with red Fuji (a bright-red apple cultivar), Huaniu apples had higher contents of (−)-epicatechin (EC), (−)-epigallocatechin (EGC), (−)-gallocatechin gallate (GCG), and procyanidins (PCs) B2 and C1 in the peel, which implies that the polymerization of the flavanols and PCs may be correlated with the dark-red skin of the fruit. Using EC as a substrate, we purified an enzyme from Huaniu peel. We performed protein sequencing and discovered that the enzyme was a polyphenol oxidase (PPO). The molecular weight of the enzyme was approximately 140 kDa, which we estimated by native-PAGE and SDS-PAGE, while it was 61 kDa by urea-SDS-PAGE, from which we discovered that the PPO was a dimer. We observed the lowest K(m) value for catechol (0.60 mM), and the best substrate was 4-methylcatechol, with a V(max) of 526.32 U mg(−1) protein. EC is a suitable natural substrate, with a K(m) value of 1.17 mM, and 55.27% of the V(max)/K(m) of 4-methylcatechol. When we used EC as a substrate, the optimum temperature and pH of the PPO were 25 °C and 5.0, respectively. In summary, we purified a dimeric PPO from Huaniu apples that showed high activity to EC, which might catalyze the polymerization of flavanols and PCs and lead to the dark-red color development of the fruit. MDPI 2022-06-17 /pmc/articles/PMC9223062/ /pubmed/35741987 http://dx.doi.org/10.3390/foods11121790 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Liu, Bin Zhou, Xianfang Guan, Haiyan Pang, Xuequn Zhang, Zhaoqi Purification and Characterization of a Dark Red Skin Related Dimeric Polyphenol Oxidase from Huaniu Apples |
title | Purification and Characterization of a Dark Red Skin Related Dimeric Polyphenol Oxidase from Huaniu Apples |
title_full | Purification and Characterization of a Dark Red Skin Related Dimeric Polyphenol Oxidase from Huaniu Apples |
title_fullStr | Purification and Characterization of a Dark Red Skin Related Dimeric Polyphenol Oxidase from Huaniu Apples |
title_full_unstemmed | Purification and Characterization of a Dark Red Skin Related Dimeric Polyphenol Oxidase from Huaniu Apples |
title_short | Purification and Characterization of a Dark Red Skin Related Dimeric Polyphenol Oxidase from Huaniu Apples |
title_sort | purification and characterization of a dark red skin related dimeric polyphenol oxidase from huaniu apples |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9223062/ https://www.ncbi.nlm.nih.gov/pubmed/35741987 http://dx.doi.org/10.3390/foods11121790 |
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