In enzymology, a lignin peroxidase (EC 1.11.1.14) is an enzyme that catalyzes the chemical reaction

1,2-bis(3,4-dimethoxyphenyl)propane-1,3-diol + H₂O₂ ${\displaystyle \rightleftharpoons }$ 3,4-dimethoxybenzaldehyde + 1-(3,4-dimethoxyphenyl)ethane-1,2-diol + H₂O

Thus, the two substrates of this enzyme are 1,2-bis(3,4-dimethoxyphenyl)propane-1,3-diol and H₂O₂, whereas its 3 products are 3,4-dimethoxybenzaldehyde, 1-(3,4-dimethoxyphenyl)ethane-1,2-diol, and H₂O.

This enzyme belongs to the family of oxidoreductases, specifically those acting on a peroxide as acceptor (peroxidases) and can be included in the broad category of ligninases. The systematic name of this enzyme class is 1,2-bis(3,4-dimethoxyphenyl)propane-1,3-diol:hydrogen-peroxide oxidoreductase. Other names in common use include diarylpropane oxygenase, ligninase I, diarylpropane peroxidase, LiP, diarylpropane:oxygen,hydrogen-peroxide oxidoreductase (C-C-bond-cleaving). It employs one cofactor, heme.

Background

Lignin is highly resistant to biodegradation and only higher fungi and some bacteria are capable of degrading the polymer via an oxidative process. This process has been studied extensively in the past twenty years, but the mechanism has not yet been fully elucidated.

Lignin is found to be degraded by enzyme lignin peroxidases produced by some fungi like Phanerochaete chrysosporium. The mechanism by which lignin peroxidase (LiP) interacts with the lignin polymer involves veratrole alcohol, which is a secondary metabolite of white rot fungi that acts as a cofactor for the enzyme.

Structural studies

As of late 2007, 3 structures have been solved for this class of enzymes, with PDB accession codes 1B80, 1B82, and 1B85.

References

• K.E.L. Eriksson; R.A. Blanchette; P. Ander (1990). Microbial and Enzymatic Degradation of Wood and Wood Components. Springer-Verlag.
• Hans E. Schoemaker; Klaus Piontek (1996). "On the interaction of lignin peroxidase with lignin". Pure and Applied Chemistry. 68 (11): 2089–96. doi:10.1351/pac199668112089. S2CID 34951982.
• Paszczynski A; Huynh VB; Crawford R (1986). "Comparison of ligninase-I and peroxidase-M2 from the white-rot fungus Phanerochaete chrysosporium". Arch. Biochem. Biophys. 244 (2): 750–65. doi:10.1016/0003-9861(86)90644-2. PMID 3080953.
• Renganathan V; Miki K; Gold MH (1985). "Multiple molecular forms of diarylpropane oxygenase, an H2O2-requiring, lignin-degrading enzyme from Phanerochaete chrysosporium". Arch. Biochem. Biophys. 241 (1): 304–14. doi:10.1016/0003-9861(85)90387-X. PMID 4026322.
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• Doyle WA, Blodig W, Veitch NC, Piontek K, Smith AT (1998). "Two substrate interaction sites in lignin peroxidase revealed by site-directed mutagenesis". Biochemistry. 37 (43): 15097–105. doi:10.1021/bi981633h. PMID 9790672.
• Wariishi H, Marquez L, Dunford HB, Gold MH (1990). "Lignin peroxidase compounds II and III. Spectral and kinetic characterization of reactions with peroxides". J. Biol. Chem. 265 (19): 11137–42. doi:10.1016/S0021-9258(19)38568-0. PMID 2162833.
• Cai DY, Tien M (1990). "Characterization of the oxycomplex of lignin peroxidases from Phanerochaete chrysosporium: equilibrium and kinetics studies". Biochemistry. 29 (8): 2085–91. doi:10.1021/bi00460a018. PMID 2328240.
• Tien M, Tu CP (1987). "Cloning and sequencing of a cDNA for a ligninase from Phanerochaete chrysosporium". Nature. 326 (6112): 520–3. Bibcode:1987Natur.326..520T. doi:10.1038/326520a0. PMID 3561490. S2CID 4321253.
• Renganathan V, Miki K, Gold MH (1986). "Role of molecular oxygen in lignin peroxidase reactions". Arch. Biochem. Biophys. 246 (1): 155–61. doi:10.1016/0003-9861(86)90459-5. PMID 3754412.
• Kersten PJ, Tien M, Kalyanaraman B, Kirk TK (1985). "The ligninase of Phanerochaete chrysosporium generates cation radicals from methoxybenzenes". J. Biol. Chem. 260 (5): 2609–12. doi:10.1016/S0021-9258(18)89401-7. PMID 2982828.
• Kirk TK, Farrell RL (1987). "Enzymatic "combustion": the microbial degradation of lignin". Annu. Rev. Microbiol. 41: 465–505. doi:10.1146/annurev.mi.41.100187.002341. PMID 3318677.