Date

December 1981

Document Type

Thesis

Degree Name

M.S.

Department

Dept. of Biochemistry

Institution

Oregon Graduate Center

Abstract

The hydroxylation and cleavage of conjugated aryl olefins by horseradish peroxidase and Phanerochaete chrysosporium were investigated, and optimum incubation conditions for the enzyme reaction were developed. Substrate specificity experiments showed that the enzyme specificity corresponded roughly to that exhibited by the fungus, with the exception that P. chrysosporium also readily degraded the mono-substituted m- and p-methoxycinnamyl alcohols to their corresponding anisyl alcohols. The pathways employed by the two systems were shown to be different. [superscript 18]O tracer studies showed that the organism probably utilized the hydroxylation product as an intermediate, confirming earlier reports by other workers. (The peroxidase, however, appears to cleave the olefin directly, in addition to catalyzing the hydroxylation reaction. It is not able to cleave the hydroxylated products.) Both peroxidase and laccase purified from Polyporus versicolor incorporated labeled oxygen only onto the B-carbon of 4-0- ethylisoeugenol, whereas P. chrysosporium incorporated a significant amount at the benzylic carbon. In addition, the ability of the fungus to perform the hydroxylation reaction in the presence of catalase suggests that the phenol oxidase(s) of P. chrysosporium are not the sole catalytic agent(s) in the metabolism of lignin-related aryl olefins.

Identifier

doi:10.6083/M4KK98PN

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