Peroxidase-catalyzed polymerization of phenols: Kinetics of p-cresol oxidation in organic media

Keungarp Ryu, Douglas R. Stafford, Jonathan S. Dordick

Research output: Contribution to journalConference articlepeer-review

32 Scopus citations

Abstract

Horseradish peroxidase is up to 5.4 times more active in high concentrations of dioxane and methanol than in aqueous buffer, as determined by values of kcat (the catalytic turnover number), when the intraparticle and external diffusional limitations, normally associated with enzymatic catalysis in monophasic organic solvents are eliminated. In model reaction systems consisting of p-cresol, hydrogen peroxide, and dioxane, methanol, or acetone (each in concentrations ranging from 60-95% v/v), horseradish peroxidase catalyzed the initial oxidation of p-cresol to 2,2′-dihydroxy-5,5′-dimethylbiphenyl (biscresol) as a major product. At longer reaction times, polymeric material was formed. Effect of the organic solvents on peroxidase was primarily to increase the Km of p-cresol. This increase was often dramatic with Km of p-cresol in 80% methanol over 2 orders of magnitude larger than in aqueous buffer.

Original languageEnglish
Pages (from-to)141-157
Number of pages17
JournalACS Symposium Series
Issue number389
StatePublished - 1989
Externally publishedYes
EventThird Chemical Congress of North America (195th National Meeting of the American Chemical Society) - Biocatalysis in Agricultural Biotechnology - Toronto, Ont, Can
Duration: 5 Jun 198811 Jun 1988

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