Date of Award

5-1-1970

Document Type

Thesis

Degree Name

Master of Science (M.S.) in Chemistry

Department

Chemistry

Physical Description

1 online resource (2, iii, 35 leaves)

Subjects

Polyphenol oxidase, Pear

DOI

10.15760/etd.688

Abstract

Polyphenolases (O-diphenol: O₂ oxidoreductase E.C. 1.10.3.1) have been isolated from a wide variety of plant and animal sources. This work deals with the isolation and characterization of polyphenolase from a previously unreported source, Pyrus communis, the common pear, horticultural variety D'Anjou. The chronometric method of assay was used, in which the enzymic oxidation of the substrate, usually catechol, is coupled to the oxidation of ascorbic acid and the time required to oxidize a specific amount of substrate is noted as the time required to colorize an external startch-iodide indicator. Various methods of isolation and purification were attempted. After a suitable isolation procedure was established, the enzyme was characterized by its substrate specificity, and its sensitivity to temperature, pH and inhibitors. Pear polyphenolase was characterized in particulate and soluble forms. The enzyme differs from other reported catechol oxidases in that it does not oxidize monophenols. A new spectrophotometric assay is described.

Description

Portland State University. Dept. of Chemistry

Persistent Identifier

http://archives.pdx.edu/ds/psu/9422

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