Aspartokinase of Lemna paucicostata Hegelm. 6746
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منابع مشابه
Aspartokinase of Lemna paucicostata Hegelm. 6746.
A sensitive and specific method was developed for assay of aspartokinase (EC 2.7.2.4) in crude extracts of Lemna paucicostata. Lysine inhibited approximately 93%, and threonine approximately 6%; together, these amino acids inhibited 99%. Inhibition by lysine was synergistically increased by S-adenosylmethionine, which by itself had no effect on activity. Essentially complete inhibition of threo...
متن کاملThreonine Synthase of Lemna paucicostata Hegelm. 6746.
Threonine synthase (TS) was purified approximately 40-fold from Lemna paucicostata, and some of its properties determined by use of a sensitive and specific assay. During the course of its purification, TS was separated from cystathionine gamma-synthase, establishing the separate identity of these enzymes. Compared to cystathionine gamma-synthase, TS is relatively insensitive to irreversible in...
متن کاملUptake of Choline and Ethanolamine by Lemna paucicostata Hegelm. 6746.
Lemna paucicostata Hegelm. 6746 possesses specific systems for uptake of choline and ethanolamine. Each is distinct from the six other systems for uptake of organic compounds so far identified in this plant. Both systems show biphasic kinetics, so that uptake by them can be described as the composite result of two Michaelis-Menten processes. Inhibitor studies are reported which indicate the ver...
متن کاملLemna paucicostata Hegelm. 6746: LIFE CYCLE AND CHARACTERIZATION OF THE COLONY TYPES IN A POPULATION.
The sequence of frond emergence and the intervals required for daughter colony separation have been determined for Lemna paucicostata Hegelm. 6746 growing under standardized conditions. After separation of a new mother colony, the first daughter colony is produced from the left meristematic pocket and separates after approximately 60 hours, the second daughter, produced from the right pocket, s...
متن کاملRegulatory Structure of the Biosynthetic Pathway for the Aspartate Family of Amino Acids in Lemna paucicostata Hegelm. 6746, with Special Reference to the Role of Aspartokinase.
Comprehensive studies were made with Lemna paucicostata Hegelm. 6746 of the effects of combinations of lysine, methionine, and threonine on growth rates, soluble amino acid contents, aspartokinase activities, and fluxes of 4-carbon moieties from aspartate through the aspartokinase step into the amino acids of the aspartate family. These studies show that flux in vitro through the aspartokinase ...
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ژورنال
عنوان ژورنال: Plant Physiology
سال: 1989
ISSN: 0032-0889,1532-2548
DOI: 10.1104/pp.90.4.1577