Compartmentation of phenylacetic and cinnamic acid synthesis in spinach |
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Authors: | Annette Bitsch Rainer Trihbes Gernot Schultz |
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Affiliation: | Inst. für Botanik, Univ. Hannover, Herrenhäuserstrasse 2, D-3000 Hannover 21, West Germany;;R. Trihbes, Botanisches Inst., Tierärztliche Hochschule Hannover, Bünteweg 17 d, D-3000 Hannover 71, West Germany. |
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Abstract: | Applying labelled phenylalanine or tyrosine to purified intact spinach chloroplasts, only the corresponding phenylacetic acids but not the cinnamic acids could be detected. The addition of mercaptoethanol or dl -dithiothreitol and the variation of light conditions had only a slight effect. However, cinnamic acids could be found together with phenylacetic acids in leaf homogenates indicating the presence of phenylalanine and/or tyrosine ammonia lyase outside the spinach chloroplasts. Similar results were obtained with barley leaf homogenates, where cinnamic acids were the main products. Reviewing recent findings on amino acid synthesis in spinach leaves, it may be concluded that the synthesis of aromatic amino acids is restricted to the chloroplast, whereas the metabolism of secondary aromatic compounds is predominantly localized outside the chloroplasts. |
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Keywords: | Aromatic acid metabolism Hordeum vulgare Spinacia oleracea |
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