Sinapyl alcohol-specific peroxidase isoenzyme catalyzes the formation of the dehydrogenative polymer from sinapyl alcohol

Abstract

Two peroxidases, CWPO-A and CWPO-C, were isolated from the cell walls of poplar (Populus alba L.) callus culture. The cationic CWPO-C showed a strong preference for sinapyl alcohol over coniferyl alcohol as substrate. Thus, the monolignol utilization of CWPO-C is unique compared with other peroxidases, including anionic CWPO-A and horseradish peroxidase (HRP). CWPO-C polymerized oligomeric sinapyl alcohol (S-oligo) and sinapyl alcohol, producing a polymer of greater molecular weight. In contrast, HRP, which is specific to coniferyl alcohol, produced sinapyl alcohol dimers, rather than catalyzing polymerization. Adding coniferyl alcohol as a radical mediator in the HRP-mediated reaction did not result in S-oligo polymerization. This report shows that CWPO-C is an isoenzyme specific to sinapyl alcohol that polymerizes oligomeric lignols. Its catalytic activity toward oligomeric lignols may be related to the lignification of angiosperm woody plant cell walls.

The cationic cell-wall-peroxidase having oxidation ability for polymeric substrate participates in the late stage of lignification of Populus alba L

“…In this regard, we previously reported that a peroxidase isoenzyme, CWPO-C, oxidizes both monolignols and synthetic high molecular weight lignin. Its enzymatic characteristics strongly support that CWPO-C is a lignification specific peroxidase (Sasaki et al 2004;Aoyama et al 2002).…”

“…The callus was maintained on the medium at 25°C in the dark. Peroxidase isoenzyme (CWPO-C) was purified from poplar callus as described by Aoyama et al (Aoyama et al 2002). The poplar tree (P. alba) was grown in Kyushu University and used for experiments of CWPO-C cloning, transcript, and localization analysis.…”

“…Previously, we reported that a peroxidase izoenzyme (Cell Wall Peroxidase-Cationic, CWPO-C) from poplar callus preferentially uses sinapyl alcohol and syringaldazine as substrates unlike other plant peroxidases. Furthermore, CWPO-C oxidizes polymer substrates synthetic of lignin polymer and ferrocytochrome c (Sasaki et al 2004;Aoyama et al 2002;Tsutsumi et al 1998). Therefore, the kinetic study suggests that CWPO-C is a specific peroxidase isoenzyme responsible for the lignification of plant cell walls.…”

Role of Tyr residues on the protein surface of cationic cell-wall-peroxidase (CWPO-C) from poplar: Potential oxidation sites for oxidative polymerization of lignin

“…An unique peroxidase isoenzyme from poplar callus, cationic cell-wall-bound peroxidase (CWPO-C), has broad substrate versatility and was reported to use sinapyl alcohol 2 and syringaldazine 6 as preferred substrates (Tsutsumi et al, , 1998Aoyama et al, 2002;Sasaki et al, 2004). Furthermore, CWPO-C catalyzes the oxidation of synthetic lignin polymers and ferrocytochrome c, unlike other plant peroxidases (Sasaki et al, 2004).…”

Mutagenesis, heterogeneous gene expression, and purification and amino acid substitution analyses of plant peroxidase, PrxA3a

“…On the other hand, cationic cell wall-bound peroxidase (CWPO-C) from poplar could catalyze the oxidation of sinapyl alcohol as preferred substrate [17][18][19][20][21]. Furthermore, CWPO-C could catalyze oxidation of synthetic lignin polymers and ferrocytochrome c, unlike other plant peroxidases [21].…”