title: Molecular cloning and partial characterization of a peroxidase gene expressed in the roots of Portulaca oleracea cv., one potentially useful in the remediation of phenolic pollutants.
abstract: Portulaca (Portulaca oleracea cv.) efficiently removes phenolic pollutants from hydroponic solution. In plant roots, peroxidase (PRX) is thought to be involved in the removal of phenolic pollutants by the cross-linking them to cell wall polysaccharides or proteins at the expense of reduction of hydrogen peroxide (H(2)O(2)). In this study, we found that portulaca roots secreted an acidic PRX isozyme that had relatively high H(2)O(2) affinity. We isolated five PRX genes, and the recombinant PRX proteins produced in cultured tobacco cells were partially characterized. Among these genes, PoPRX2 probably encoded the acidic PRX isozyme. PoPRX2 had an extra N-terminal region which has not been reported for other PRX proteins. We found that PoPRX2 oxidized phenolic pollutants, including bisphenol A, octylphenol, nonylphenol, and 17β-estradiol. In addition, we found that the Cys261 residue of PoPRX2 played an important role in the determination of affinity for H(2)O(2) and stability toward H(2)O(2).
authors: Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Nara, Japan.
authors: Takeshi
authors: T
authors: Matsui
authors: Yuki
authors: Y
authors: Nomura
authors: Mai
authors: M
authors: Takano
authors: Sofue
authors: S
authors: Imai
authors: Hideki
authors: H
authors: Nakayama
authors: Hitoshi
authors: H
authors: Miyasaka
authors: Hiroshi
authors: H
authors: Okuhata
authors: Satoshi
authors: S
authors: Tanaka
authors: Hideyuki
authors: H
authors: Matsuura
authors: Kazuo
authors: K
authors: Harada
authors: Takeshi
authors: T
authors: Bamba
authors: Kazumasa
authors: K
authors: Hirata
authors: Ko
authors: K
authors: Kato