Oxidative cleavage of a phenolic diarylpropane lignin model dimer by manganese peroxidase from Phanerochaete chrysosporium

Journal Article · Tue Jul 11 00:00:00 EDT 1989 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00440a044· OSTI ID:5084836

Wariishi, Hiroyuki; Valli, K; Gold, M H ^[1]

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1. Oregon Graduate Center, Beaverton (USA)

In the presence of Mn{sup II} and H{sub 2}O{sub 2}, homogeneous manganese peroxidase oxidized 1-(3,5-dimethoxy-4-hydroxy phenyl)-2- (4-methoxyphenyl)- 1,3-dihydroxypropane (I) to yield 1-(3,5- dimethoxy-4- hydroxyphenyl)-2- (4-methoxyphenyl)-1-oxo-3- hydroxy propane (II), 2,6-dimethoxy- 1,4-benzoquinone (III), 2,6-dimethoxy- 1,4-dihydroxy benzene (IV), 1-(4-methoxyphenyl)- 1-oxo-2-hydroxyethane (V), 1-(4-methoxyphenyl)- 1,2-dihydroxyethane (VI), syringaldehyde (VIII), and 2-(4-methoxyphenyl)- 3-hydroxypropanal (IX). Chemically prepared manganese(III) malonate catalyzed the same reactions. Oxidation of I in H{sub 2}{sup 18}O under argon resulted in >80% incorporation of {sup 18}O into the phenylglycol VI, the hydroquinone IV, and the quinone III. Oxidation of I in H{sub 2}{sup 18}O under aerobic conditions resulted in 40% incorporation of {sup 18}O into VI but no {sup 18}O incorporation into V. Finally, oxidation of I under {sup 18}O{sub 2} resulted in 89% and 28% incorporation of {sup 18}O into V and VI, respectively. These results are explained by mechanisms involving the one-electron oxidation of the substrate I by enzyme-generated Mn{sup III} to produce a phenoxy radical intermediate I{prime}. Subsequent C{sub {alpha}}-C{sub {beta}} bond cleavage of the radical intermediate yields syringaldehyde (VIII) and a C{sub 6}-C{sub 2} benzylic radical. Syringaldehyde is oxidized by Mn{sup III} in several steps to a cyclohexadiene cation intermediate I{double prime}, which is attacked by water to yield the benzoquinone III. The C{sub 6}-C{sub 2} radical is scavenged by O{sub 2} to form a peroxy radical that decomposes to V and VI. In these reactions, Mn{sup III} generated by manganese peroxidase catalyzes both formation of the substrate phenoxy radical and oxidation of carbon-centered radical intermediates, to yield reactive cations.

• DOE Contract Number: FG06-86ER13550
• OSTI ID: 5084836
• Journal Information: Biochemistry; (USA), Vol. 28:14; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
LIGNIN
OXIDATION
OXYGEN 18
UPTAKE
PEROXIDASES
BIOCHEMISTRY
BIODEGRADATION
HYDROGEN PEROXIDE
MANGANESE SULFATES
MASS SPECTROSCOPY
SUBSTRATES
CARBOHYDRATES
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
ENZYMES
EVEN-EVEN NUCLEI
HYDROGEN COMPOUNDS
ISOTOPES
LIGHT NUCLEI
MANGANESE COMPOUNDS
NUCLEI
ORGANIC COMPOUNDS
OXIDOREDUCTASES
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
PEROXIDES
POLYSACCHARIDES
SACCHARIDES
SPECTROSCOPY
STABLE ISOTOPES
SULFATES
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
550201* - Biochemistry- Tracer Techniques