Volume 1, Issue 2 pp. 93-110
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PROPERTIES OF IAA OXIDASE FROM RIPENING TOMATO FRUIT

ANN E. HUANG

ANN E. HUANG

Department of Food Science Rutgers, The State University Cook College New Brunswick, New Jersey 08903

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NORMAN F. HAARD

NORMAN F. HAARD

Department of Food Science Rutgers, The State University Cook College New Brunswick, New Jersey 08903

Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland, Canada A1C-5S7

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First published: April 1977
Citations: 14

Abstract

An indoleacetic acid (IAA) oxidizing enzyme was isolated from the pericarp of ripening tomato fruit by column chromatography fractionation. IAA oxidase from extracts of tomato pericarp exists in a high molecular weight form (>200,000) or in a low molecular weight form (∼40,000) or both depending upon extraction procedures. When IAA was oxidized by the high molecular weight form of IAA oxidase, a relatively long lag time was observed. The low molecular weight form of IAA oxidase activity showed no lag or a very short, 1- to 2-minute lag period. Enzyme activity was optimal at pH 6.1 and was stimulated by 2,4-dichlorophenol (DCP) and MnCl2. Neither 3-methyleneoxindole nor indolealdehyde were found as a major IAA oxidation products. Moderate increase in activity of IAA oxidase activity was observed during ripening of tomato fruit.

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