The Conversion of d-Tryptophan to l-Tryptophan in Cell Cultures of Tobacco.
d-Tryptophan was converted to l-tryptophan in tissue cultures of tobacco, in whole cells treated with dimethylsulfoxide, and in cell-free extracts treated by Sephadex G-25 filtration. Evidence was obtained that tryptophanase, tryptophan pyrrolase, and transaminase activities were not involved. The data were best explained by the presence of a tryptophan racemase as the enzyme catalyzing the reaction. The possible role of d-tryptophan in the biosynthesis of indoleacetic acid is discussed.
Miura
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Department of Biology, University of California, San Diego, La Jolla, California 92037.
Mills
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