ID   1.11.1.14
DE   lignin peroxidase.
AN   diarylpropane oxygenase.
AN   diarylpropane peroxidase.
AN   ligninase I.
AN   LiP.
CA   (1) 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)propane-1,3-diol + H2O2 =
CA   3,4-dimethoxybenzaldehyde + glycolaldehyde + guaiacol + H2O.
CA   (2) 2 (3,4-dimethoxyphenyl)methanol + H2O2 = 2 (3,4-
CA   dimethoxyphenyl)methanol radical + 2 H2O.
CC   -!- Involved in the oxidative breakdown of lignin by white-rot
CC       basidiomycete fungi.
CC   -!- The reaction involves an initial oxidation of the heme iron by
CC       hydrogen peroxide, forming compound I (Fe(IV)=O radical cation) at
CC       the active site.
CC   -!- A single one-electron reduction of compound I by an electron derived
CC       from a substrate molecule yields compound II (Fe(IV)=O non-radical
CC       cation), followed by a second one-electron transfer that returns the
CC       enzyme to the ferric oxidation state.
CC   -!- The electron transfer events convert the substrate molecule into a
CC       transient cation radical intermediate that fragments spontaneously.
CC   -!- The enzyme can act on a wide range of aromatic compounds, including
CC       methoxybenzenes and nonphenolic beta-O-4 linked arylglycerol beta-
CC       aryl ethers, but cannot act directly on the lignin molecule, which is
CC       too large to fit into the active site.
CC   -!- However larger lignin molecules can be degraded in the presence of
CC       veratryl alcohol.
CC   -!- It has been suggested that the free radical that is formed when the
CC       enzyme acts on veratryl alcohol can diffuse into the lignified cell
CC       wall, where it oxidizes lignin and other organic substrates.
CC   -!- In the presence of high concentration of hydrogen peroxide and lack
CC       of substrate, the enzyme forms a catalytically inactive form
CC       (compound III).
CC   -!- This form can be rescued by interaction with two molecules of the
CC       free radical products.
CC   -!- In the case of veratryl alcohol, such an interaction yields two
CC       molecules of veratryl aldehyde.
DR   P49012, LIG2_PHACH ;  P21764, LIG3_PHACH ;  P11542, LIG4_PHACH ;
DR   P11543, LIG5_PHACH ;  P50622, LIG6_PHACH ;  P06181, LIG8_PHACH ;
DR   P31837, LIGA_PHACH ;  P20011, LIGA_TRAVE ;  P31838, LIGB_PHACH ;
DR   P20012, LIGB_TRAVE ;  P20013, LIGC_TRAVE ;  P20010, LIG_PHLRA  ;
//