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The effect of aspartate-derived amino acids (lysine, threonine, methionine) on the growth of excised embryos of wheat and barley

โœ Scribed by Simon W. J. Bright; Elizabeth A. Wood; Benjamin J. Miflin

Publisher
Springer-Verlag
Year
1978
Tongue
English
Weight
423 KB
Volume
139
Category
Article
ISSN
0032-0935

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โœฆ Synopsis

Excised wheat (Triticum aestivum L. var. Maris Freeman) and barley (Hordeum vulgare L. var. Maris Mink) embryos were grown on medium containing both nitrate and ammonium ions. Addition of lysine (1 mM) plus threonine (1 mM) caused a synergistic inhibition of growth measured by length of first leaf or dry weight. The inhibition was specifically relieved by methionine, homocysteine and homoserine. Threonine at 0.2-0.3 mM caused half-maximal inhibition of growth at all lysine concentrations whereas lysine increased the synergistic inhibition up to 3 mM. The inhibition is explained by a model in which lysine acts as a feedback inhibitor of aspartate kinase and threonine of homoserine dehydrogenase. This is compatible with published studies of the enzymes involved. The implications of these findings for using lysine plus threonine as a selection system for lysine-overproducing cereals are discussed.

๐Ÿ“œ SIMILAR VOLUMES

Microbial production of amino acids. II.
Microbial production of amino acids. II. The influence of carbon and nitrogen sources and metal ions on growth of Ustilago maydis (DC.) Cda. and on lysine and threonine production
โœ W. G. Kurz; L.-E. Ericson ๐Ÿ“‚ Article ๐Ÿ“… 1962 ๐Ÿ› John Wiley and Sons ๐ŸŒ English โš– 671 KB

## Abstract The ability of __Ustilago maydis__ (DC.) Cda. to grow and to produce lysine and threonine was investigated in shake flask cultures. Growth and production of lysine and threonine increased markedly when aeration was increased. The optimal ratio of glucose to diammonium phosphate in the m