Plant Physiol. Illumina
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Plant Physiology 86:369-377 (1988)
© 1988 American Society of Plant Biologists

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Web of Science (17)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Giovanelli, J.
Right arrow Articles by Datko, A. H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Giovanelli, J.
Right arrow Articles by Datko, A. H.
Agricola
Right arrow Articles by Giovanelli, J.
Right arrow Articles by Datko, A. H.
Metabolism and Enzymology

In Vivo Regulation of Threonine and Isoleucine Biosynthesis in Lemna paucicostata Hegelm. 6746

John Giovanelli1, S. Harvey Mudd and Anne H. Datko

Laboratory of General and Comparative Biochemistry, National Institute of Mental Health, Bethesda, Maryland 20892

Little, if any, regulation of threonine synthesis was observed in Lemna paucicostata Hegelm. 6746 supplemented with concentrations of threonine and/or isoleucine that allow for uptake of these amino acids in amounts sufficient for total plant requirements, and that increase tissue concentrations of soluble threonine manyfold. High tissue concentrations of soluble threonine generated endogenously in isoleucine-supplemented plants were no more effective in regulation than a similar concentration of threonine accumulated from the medium. These studies exclude also major regulation of threonine biosynthesis by bivalent repression by threonine plus isoleucine. Isoleucine biosynthesis was severely inhibited by supplementation with isoleucine, but not with threonine or methionine. The fivefold increase in soluble threonine in isoleucine-supplemented plants suggests that threonine dehydratase is a major locus for feedback regulation of isoleucine synthesis. It is concluded that regulation of threonine biosynthesis differs from that of the other amino acids of the aspartate family (isoleucine, methionine, and lysine), each of which strongly feedback regulates its own synthesis. Methionine supplementation had a negligible effect on the tissue concentration of soluble threonine, indicating that threonine is not important in balancing changes of flux into methionine by equivalent changes of flux through the step catalyzed by aspartokinase.

1 Address correspondence to Building 36, Room 3D30, National Institute of Mental Health, Bethesda, MD 20892




This article has been cited by other articles:


Home page
 J Exp BotHome page
A. R. Robinson, R. Gheneim, R. A. Kozak, D. D. Ellis, and S. D. Mansfield
The potential of metabolite profiling as a selection tool for genotype discrimination in Populus
J. Exp. Bot., November 1, 2005; 56(421): 2807 - 2819.
[Abstract] [Full Text] [PDF]

Home page
 Plant Physiol.Home page
D. Bartlem, I. Lambein, T. Okamoto, A. Itaya, Y. Uda, F. Kijima, Y. Tamaki, E. Nambara, and S. Naito
Mutation in the Threonine Synthase Gene Results in an Over-Accumulation of Soluble Methionine in Arabidopsis
Plant Physiology, May 1, 2000; 123(1): 101 - 110.
[Abstract] [Full Text]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
ASPB Publications PLANT PHYSIOLOGY® THE PLANT CELL
Copyright © 1988 by the American Society of Plant Biologists