Stimulation of Mn peroxidase activity: A possible role for oxalate in lignin biodegradation

Journal Article · Mon Feb 15 00:00:00 EST 1993 · Proceedings of the National Academy of Sciences of the United States of America; (United States)

DOI:https://doi.org/10.1073/pnas.90.4.1242· OSTI ID:6653625

Kuan, Iching; Tien, Ming ^[1]

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1. Pennsylvania State Univ., University Park (United States)

Oxalate is produced by numerous wood-degrading fungi. Our studies here show that the white-rot fungus Phaerochaete chrysosporium produces extracellular exalate under conditions that induce synthesis of the ligninolytic system. Little or no oxalate was detected in cultures grown under high nutrient nitrogen or carbon. This extracellular exalate was identified and quantitated by HPLC. Its identity was further substaintiated by its decomposition by the enzyme oxalate oxidase. The oxalate content of the extracellular fluid (peaking at 60 [mu]M) paralleled the extracellular activity of the lignin-degrading enzyme, Mn peroxidase. Significantly, we demonstrated that oxalate, at physiological concentrations, substantially stimulated Mn perosidase-catalyzed phenol red oxidation, presumably by its ability to chelate Mn. Stopped flow studies also indicate that oxalate accelerates the turnover of Mn peroxidase. Furthermore, we discovered that oxalate can support Mn peroxidase-catalyzed oxidations in the absence of exogenous H[sub 2]O[sub 2] and in the presence of dioxygen. These results allow us to propose an important role for oxalate, a ubiquitous compound produced by wood-destroying fungi, in lignin biodegradation. 27 refs., 5 figs.

• DOE Contract Number: FG02-87ER13690
• OSTI ID: 6653625
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (United States), Vol. 90:4; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ENZYME ACTIVITY
STIMULATION
LIGNIN
BIODEGRADATION
CARBON
DECOMPOSITION
FUNGI
MANGANESE
NITROGEN
OXALATES
PEROXIDASES
SYNTHESIS
WOOD
CARBOHYDRATES
CARBOXYLIC ACID SALTS
CHEMICAL REACTIONS
ELEMENTS
ENZYMES
METALS
NONMETALS
ORGANIC COMPOUNDS
OXIDOREDUCTASES
PLANTS
POLYSACCHARIDES
PROTEINS
SACCHARIDES
TRANSITION ELEMENTS
550200* - Biochemistry