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Song J, Liu C, Li D, Gu Z. Postharvest changes in physicochemical characteristics and free amino acids content of immature vegetable soya bean (Glycine maxL.) grains. Int J Food Sci Technol 2015. [DOI: 10.1111/ijfs.13004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jiangfeng Song
- Institute of Farm Product Processing; Jiangsu Academy of Agricultural Sciences; Nanjing 210014 China
- College of Food Science and Technology; Nanjing Agricultural University; Nanjing 210095 China
| | - Chunquan Liu
- Institute of Farm Product Processing; Jiangsu Academy of Agricultural Sciences; Nanjing 210014 China
| | - Dajing Li
- Institute of Farm Product Processing; Jiangsu Academy of Agricultural Sciences; Nanjing 210014 China
| | - Zhenxin Gu
- College of Food Science and Technology; Nanjing Agricultural University; Nanjing 210095 China
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Fowden L, Lea PJ, Bell EA. The nonprotein amino acids of plants. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 50:117-75. [PMID: 386718 DOI: 10.1002/9780470122952.ch3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Avraham T, Amir R. The expression level of threonine synthase and cystathionine-γ-synthase is influenced by the level of both threonine and methionine in Arabidopsis plants. Transgenic Res 2005; 14:299-311. [PMID: 16145838 DOI: 10.1007/s11248-005-0273-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The biosynthesis pathways of the essential amino acids methionine and threonine diverge from O-phosphohomoserine, an intermediate metabolite in the aspartate family of amino acids. Thus, the enzymes cystathionine-gamma-synthase (CGS) in the methionine pathway and threonine synthase (TS), the last enzyme in the threonine pathway, compete for this common substrate. To study this branching point, we overexpressed TS in sense and antisense orientation in Arabidopsis plants with the aim to study its effect on the level of threonine but more importantly on the methionine content. Positive correlation was found not only between TS expression level and threonine content, but also between TS/threonine and CGS expression level. Plants expressing the sense orientation of TS showed a higher level of threonine, increased expression level of CGS, and a significantly higher level of S-methylmethionine, the transport form of methionine. By contrast, plants expressing the antisense form of TS showed lower levels of threonine and of CGS expression level. In these antisense plants, the methionine level increased up to 47-fold compared to wild-type plants. To study further the effect of threonine on CGS expression level, wild-type plants were irrigated with threonine and control plants were irrigated with methionine or water. While threonine increased the expression level of CGS but reduced that of TS, methionine reduced the expression level of CGS but increased that of TS. This data demonstrate that both methionine and threonine affect the two enzymes at the branching point, thus controlling not only their own level, but also the level of each other. This mechanism probably aids in keeping the levels of these two essential amino acids sufficiently high to support plant growth.
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Affiliation(s)
- Tal Avraham
- Plant Science Laboratory, Migal Galilee Technology Center, P O Box 831, Kiryat Shmona 11016, Israel
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Azevedo RA, Arruda P, Turner WL, Lea PJ. The biosynthesis and metabolism of the aspartate derived amino acids in higher plants. PHYTOCHEMISTRY 1997; 46:395-419. [PMID: 9332022 DOI: 10.1016/s0031-9422(97)00319-1] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The essential amino acids lysine, threonine, methionine and isoleucine are synthesised in higher plants via a common pathway starting with aspartate. The regulation of the pathway is discussed in detail, and the properties of the key enzymes described. Recent data obtained from studies of regulation at the gene level and information derived from mutant and transgenic plants are also discussed. The herbicide target enzyme acetohydroxyacid synthase involved in the synthesis of the branched chain amino acids is reviewed.
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Affiliation(s)
- R A Azevedo
- Departamento de Genética, Universidade de São Paulo, Piracicaba, SP, Brasil
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Sumaryati S, Negrutiu I, Jacobs M. Characterization and regeneration of salt- and water-stress mutants from protoplast culture of Nicotiana plumbaginifolia (Viviani). TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 1992; 83:613-619. [PMID: 24202679 DOI: 10.1007/bf00226906] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/1991] [Accepted: 08/08/1991] [Indexed: 06/02/2023]
Abstract
Protoplast-derived colonies of haploid N. plumbaginifolia leaves were used to select for resistance to NaCl, KCl and polyethylene glycol 6000 (PEG). Salt-and PEG-tolerant cell lines were isolated on the basis of growth in a culture medium containing inhibitory concentrations of either NaCl or KCl (200 mM) or PEG (25%). The frequency of resistant lines ranged from 10(-5) to 10(-6). One resistant line from each treatment was regenerated into plants. All resistant lines produced 10-25 times more proline than the wild type when grown on a non-selective medium. Similar values were also observed in the leaves of resistant progeny plants. In each mutant line, salt or PEG resistance was transmitted as a single dominant nuclear gene as shown by segregation ratios in progenies of crosses between resistant and wild-type plants. The latter observation demonstrates clearly the existence of a genetic basis for increased salt tolerance.
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Affiliation(s)
- S Sumaryati
- Plantengenetica, Vrije Universiteit Brussel, Instituut voor Moleculaire Biologie, Paardenstraat 65, B-1640, St. Genesius Rode, Belgium
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Enzymes of Lysine Synthesis. ACTA ACUST UNITED AC 1990. [DOI: 10.1016/b978-0-12-461013-2.50025-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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7
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Rognes SE, Bright SW, Miflin BJ. Feedback-insensitive aspartate kinase isoenzymes in barley mutants resistant to lysine plus threonine. PLANTA 1983; 157:32-38. [PMID: 24263942 DOI: 10.1007/bf00394537] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/1982] [Accepted: 08/31/1982] [Indexed: 06/02/2023]
Abstract
The regulatory properties of aspartate kinase (EC 2.7.2.4) and homoserine dehydrogenase (EC 1.1.1.3) in two barley (Hordeum vulgare L.) mutants resistant to growth inhibition by lysine plus threonine, Rothamsted (R) 3004 and R3202, were compared with those in the normal, sensitive parent line cv. Bomi. Three forms of aspartate kinase (AKI, AKII, AKIII) were chromatographically separated and were considered to represent at least three independently regulated isoenzymes. Aspartate kinase I was inhibited by threonine; AKII and AKIII by lysine or lysine plus S-adenosylmethionine. The characteristics of AKI were unchanged in the mutants. Aspartate kinase II and AKIII from Bomi were both inhibited by lysine and by lysine plus S-adenosylmethionine. Aspartate kinase II from mutant R3202 was altered in its properties such that it was insensitive to lysine or lysine plus S-adenosylmethionine; AKII from mutant R3004 did not differ in its properties from AKII of Bomi. The concentration of lysine required to give half maximal inhibition of AKIII from R3004 was ten times that required for AKIII of Bomi; AKIII from R3202 did not differ from that of Bomi in this regard. There was no change in the properties of homoserine dehydrogenase of the mutants as compared with that of Bomi. We conclude that the lt1 and lt2 loci code for structural genes for lysine- and lysine plus S-adenosylmethionine-sensitive aspartate kinase isoenzymes. The mutant genes Lt1b and Lt2 in R3202 and R3004 respectively code for feedback-desensitized isoenzymes. The presence of one of these is sufficient to allow the synthesis of methionine to overcome the growth inhibition by lysine plus threonine.
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Affiliation(s)
- S E Rognes
- Biochemistry Department, Rothamsted Experimental Station, AL 5 2JQ, Harpenden, Herts, UK
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Bright SW, Miflin BJ, Rognes SE. Threonine accumulation in the seeds of a barley mutant with an altered aspartate kinase. Biochem Genet 1982; 20:229-43. [PMID: 6285889 DOI: 10.1007/bf00484421] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Barley (Hordeum vulgare L.) mutants altered in the regulation of synthesis of aspartate-derived amino acids were sought by screening embryos for growth on a medium containing lysine plus threonine. One mutant, Rothamsted 2501, was selected with good growth. From the segregation of resistance in the following generations, it was concluded that the resistance was conferred by a dominant gene, Lt1. No homozygous Lt1/Lt1 fertile plants have been recovered. Partially purified aspartate kinase preparations from resistant and sensitive plants were separated on DEAE-cellulose chromatography into three peaks of activity (I, II, III) and the feedback regulatory properties of these peaks determined. These peaks are considered to be three isozymic forms of aspartate kinase, one predominantly sensitive to threonine and two sensitive to lysine or lysine plus S-adenosyl methionine. The feedback characteristics of one of the peaks of aspartate kinase activity from resistant plants were changed such that lysine was half-maximally inhibitory at 10 rather than 0.4 mM. Increases in te concentrations of the free pools of threonine (4x) and methionine (2x) were measured in young plants grown on a basal medium. Threonine in the soluble fraction of mature seeds from resistant plants was increased from 0.8 to 9.6% of the total threonine content. The total content of both threonine and methionine of the seeds was increased by 6% compared with grain of similar nitrogen content.
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Fukunaga Y, King J. The effect of L-amino acids on the growth of and nitrate reductase activity in cultured cells of Datura innoxia. ACTA ACUST UNITED AC 1982. [DOI: 10.1016/0304-4211(82)90007-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Reisch BI, Duke SH, Bingham ET. Selection and characterization of ethionine-resistant alfalfa (Medicago sativa L.) cell lines. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 1981; 59:89-94. [PMID: 24276386 DOI: 10.1007/bf00285896] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/1980] [Accepted: 08/25/1980] [Indexed: 06/02/2023]
Abstract
Diploid alfalfa (HG2), capable of plant regeneration from tissue culture, was used to select variant cell lines resistant to growth inhibition due to ethionine (an analog of methionine). Approximately 10(7) suspension-cultured cells were mutagenized with methane sulfonic acid ethylester and then plated in solid media containing ethionine. Callus colonies formed on media with 0.02 mM ethionine. Of the 124 cell lines recovered, 91 regenerated plants. After six months growth on media without ethionine, 15 of 110 cell lines of callus grew significantly better than HG2 on 1 mM ethionine. Several ethionine-resistant callus cultures were also resistant to growth inhibition due to the addition of lysine + threonine to the media. High concentrations, relative to unselected HG2 callus, of methionine, cysteine, cystathionine, and glutathione were found in some, but not all, ethionine-resistant callus cultures. Cell line R32, which had a ca. tenfold increase in soluble methionine, had a 43% increase in total free amino acids and a 40% increase in amino acids in protein as compared to unselected HG2 callus. Relative amounts of each amino acid in protein were the same in both.
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Affiliation(s)
- B I Reisch
- Department of Agronomy, University of Wisconsin, Madison, Wisconsin, USA
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Bright SW, Featherstone LC, Miflin BJ. Lysine metabolism in a barley mutant resistant to S(2-aminoethyl)cysteine. PLANTA 1979; 146:629-633. [PMID: 24318338 DOI: 10.1007/bf00388843] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/1979] [Accepted: 06/01/1979] [Indexed: 06/02/2023]
Abstract
Lysine and S(2-aminoethyl)cysteine (AEC) metabolism were investigated in normal barley (Hordeum vulgare L. cv. Bomi) and a hemozygous recessive AEC-resistant mutant (R906). Feedback regulation of lysine and threonine synthesis from [(14)C] acetate was unimpaired in plants of the mutant 3 d after germination. Seeds of Bomi and R906 contained similar total amounts of lysine, threonine, methionine and isoleucine. Concentrations of these amino acids in the soluble fraction of plants grown 6 d without AEC were also similar. The concentration of AEC in R906 plants was less than in the parent variety when both were grown in the presence of 0.25 mM AEC for 6 d. The uptake of [(3)H]AEC and [(3)H]lysine by roots of R906 was, respectively, 33% and 32% of that by Bomi roots whereas the uptake of these compounds into the scutellum was the same in both the mutant and its parent. The uptake of [(3)H]leucine and its incorporation into proteins was also the same in Bomi and R906 plants. These results suggest that a transport system specific for lysine and AEC but not leucine is altered or lost in roots of the mutant R906. AEC is incorporated into protein and this could be the reason for inhibition of growth rather than action as a false-feedback inhibitor of lysine biosynthesis.
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Affiliation(s)
- S W Bright
- Biochemistry Department, Rothamsted Experimental Station, AL5 2JQ, Harpenden, Herts, U.K
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Lea PJ, Mills WR, Miflin BJ. The isolation of a lysine-sensitive aspartate kinase from pea leaves and its involvement in homoserine biosynthesis in isolated chloroplasts. FEBS Lett 1979; 98:165-8. [PMID: 218838 DOI: 10.1016/0014-5793(79)80175-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Cummings DP, Green CE, Stuthman DD. Studies on lysine analogs, aspartate-derived amino acids, and attempted mutant selection on oat seedlings. PLANTA 1979; 145:309-314. [PMID: 24317756 DOI: 10.1007/bf00388354] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/1978] [Accepted: 01/15/1979] [Indexed: 06/02/2023]
Abstract
The lysine analogs S-2-aminoethyl-L-cysteine (AEC) and DL-Δ-hydroxylysine (DHL) caused severe growth inhibition in dark-grown oat seedlings (Avena sativa L. and A. nuda L.) at similar concentrations while L-lysine methyl ester (LME) had little effect. Lysine, arginine, and ornithine reversed the inhibition caused by AEC and DHL, the order of effectiveness being lysine>arginine>ornithine. Of aspartate-pathway amino acids, tested individually and in combinations for inhibitory effects on seedling growth, lysine and combinations containing lysine were the most inhibitory, but the inhibition was much less than that produced by AEC. Only slight synergistic effects occurred when oat seedlings were grown in the presence of paired combinations of aspartatepathway endproduct amino acids.Ca. 54,000 seeds obtained from 3,463 plants grown from ethyl-methanesulfonate (EMS) treated seed were screened for resistance to AEC. Three resistant variants were identified but the resistance was not recovered among their self-pollinated progeny.
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Affiliation(s)
- D P Cummings
- Department of Agronomy and Plant Genetics, University of Minnesota, 55108, St. Paul, MN, USA
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Bright SW, Lea PJ, Miflin BJ. The regulation of methionine biosynthesis and metabolism in plants and bacteria. CIBA FOUNDATION SYMPOSIUM 1979:101-17. [PMID: 398759 DOI: 10.1002/9780470720554.ch7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The amino acids biosynthetically derived from asparate including methionine are all essential in the diet of monogastric animals. Most of this requirement is met by plant foods. The methionine biosynthetic pathways in plants and bacteria are outlined and compared. Regulation in bacterial systems is by a combination of repression and feedback inhibition whereas in plants repression is unimportant. Several enzymes in the branched pathway to methionine in plants are regulated by feedback inhibition; others are yet to be investigated. In plants may amino acid biosynthetic enzymes are localized in plastids and this is also likely for methionine biosynthesis. Methionine occupies an important position in cellular metabolism where the processes of one-carbon transfer via S-adenosylmethionine, protein synthesis, protein initiation and ethylene synthesis are interlocked. Attempts to increase the levels of free methionine have been made by selecting for plant mutants resistant to lysine plus threonine. One dominant mutation causes elevation of free amino acid levels in vegetative tissues but also has undesirable side-effects. The potential of such approaches is discussed.
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Bright SW, Wood EA, Miflin BJ. The effect of aspartate-derived amino acids (lysine, threonine, methionine) on the growth of excised embryos of wheat and barley. PLANTA 1978; 139:113-117. [PMID: 24414149 DOI: 10.1007/bf00387135] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/1977] [Accepted: 12/06/1977] [Indexed: 05/28/2023]
Abstract
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.
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Affiliation(s)
- S W Bright
- Biochemistry Department, Rothamsted Experimental Station, AL5 2JQ, Harpenden, Herts., U.K
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