2.5.1.45: homospermidine synthase (spermidine-specific)
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For detailed information about homospermidine synthase (spermidine-specific), go to the full flat file.
Reaction
Synonyms
homospermidine synthase, HSS, HSS1, synthase, homospermidine, synthase, homospermidine (Senecio vernalis root gene HSS1)
ECTree
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General Information on EC 2.5.1.45 - homospermidine synthase (spermidine-specific)
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GENERAL INFORMATION 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
evolution
malfunction
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transgenic tobacco plants are generated expressing Senecio vernalis homospermidine synthase. Analyses of the polyamine content reveals that, in the transgenic plants, about 80% of spermidine is replaced by homospermidine without any conspicuous modifications of the phenotype. Tracer-feeding experiments and gas chromatographic analyses suggest that these high levels of homospermidine are not sufficient to explain the formation of alkaloid precursors
metabolism
physiological function
additional information
evolution
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the gene encoding enzyme HSS origins from a single duplication event of a single-copy gene encoding deoxyhypusine synthase, DHS, EC 2.5.1.46. This duplication event was followed by several losses of a functional gene copy attributable to gene loss or pseudogenization. Statistical analyses of sequence data suggest that, in those lineages in which the gene copy was successfully recruited as HSS, the gene duplication event was followed by phases of various selection pressures, including purifying selection, relaxed functional constraints, and possibly positive Darwinian selection
evolution
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the gene encoding enzyme HSS origins from a single duplication event of a single-copy gene encoding deoxyhypusine synthase, DHS, EC 2.5.1.46. This duplication event was followed by several losses of a functional gene copy attributable to gene loss or pseudogenization. Statistical analyses of sequence data suggest that, in those lineages in which the gene copy was successfully recruited as HSS, the gene duplication event was followed by phases of various selection pressures, including purifying selection, relaxed functional constraints, and possibly positive Darwinian selection
evolution
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the gene encoding enzyme HSS origins from a single duplication event of a single-copy gene encoding deoxyhypusine synthase, DHS, EC 2.5.1.46. This duplication event was followed by several losses of a functional gene copy attributable to gene loss or pseudogenization. Statistical analyses of sequence data suggest that, in those lineages in which the gene copy was successfully recruited as HSS, the gene duplication event was followed by phases of various selection pressures, including purifying selection, relaxed functional constraints, and possibly positive Darwinian selection
evolution
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the gene encoding enzyme HSS origins from a single duplication event of a single-copy gene encoding deoxyhypusine synthase, DHS, EC 2.5.1.46. This duplication event was followed by several losses of a functional gene copy attributable to gene loss or pseudogenization. Statistical analyses of sequence data suggest that, in those lineages in which the gene copy was successfully recruited as HSS, the gene duplication event was followed by phases of various selection pressures, including purifying selection, relaxed functional constraints, and possibly positive Darwinian selection
evolution
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the gene encoding enzyme HSS origins from a single duplication event of a single-copy gene encoding deoxyhypusine synthase, DHS, EC 2.5.1.46. This duplication event was followed by several losses of a functional gene copy attributable to gene loss or pseudogenization. Statistical analyses of sequence data suggest that, in those lineages in which the gene copy was successfully recruited as HSS, the gene duplication event was followed by phases of various selection pressures, including purifying selection, relaxed functional constraints, and possibly positive Darwinian selection
metabolism
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homospermidine synthase is the first pathway-specific enzyme of pyrrolizidine alkaloid biosynthesis
metabolism
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homospermidine synthase is the first pathway-specific enzyme of pyrrolizidine alkaloid biosynthesis
metabolism
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homospermidine synthase is the first pathway-specific enzyme of pyrrolizidine alkaloid biosynthesis
metabolism
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homospermidine synthase is the first pathway-specific enzyme of pyrrolizidine alkaloid biosynthesis
metabolism
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homospermidine synthase is the first pathway-specific enzyme of pyrrolizidine alkaloid biosynthesis
metabolism
polymanines in Crotalaria are detectable only when the plants form nodules after infection with their rhizobial partner. But polyamines are synthesized by the plant not by the mcirosymbiont
metabolism
the enzyme is first specific enzyme in the biosynthesis of pyrrolizidine alkaloids
metabolism
the enzyme is first specific enzyme in the biosynthesis of pyrrolizidine alkaloids
metabolism
the enzyme is first specific enzyme in the biosynthesis of pyrrolizidine alkaloids, it is involved in the biosynthetic pathway of the lycopsamine-type polyamine indicine N-oxide
physiological function
RNAi knockdown of HSS in hairy roots by 60-80% results in a reduction of homospermidine by about 86% and of the major pyrrolizidine alkaloid components 7-acetylintermedine N-oxide and 3-acetylmyoscorpine N-oxide by approximately 60%
physiological function
the gene encoding isoform HSS1 is absent in some perennial ryegrass plants, and absence of the HSS1 gene is associated with lower levels of thesinine-rhamnoside pyrrolizidine alkaloids
additional information
exogenously applied nitrate has no impact on polyamine biosynthesis, and enzyme activity, but nodulation is inhibited at higher levels of nitrate by autoregulation
additional information
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the Convulvulaceae species Ipomoea alba contains ipanguline-type polyamines. Detection of sites that are involved in optimizing HSS functionality
additional information
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the Convulvulaceae species Ipomoea hederifolia contains ipanguline-type polyamines. Detection of sites that are involved in optimizing HSS functionality
additional information
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the Convulvulaceae species Ipomoea meyeri contains ipanguline- and triangularine-type polyamines. Detection of sites that are involved in optimizing HSS functionality
additional information
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the Convulvulaceae species Ipomoea neei contains ipanguline-type polyamines. Detection of sites that are involved in optimizing HSS functionality
additional information
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the Convulvulaceae species Merremia quinquefolia contains ipanguline- and triangularine-type polyamines. Detection of sites that are involved in optimizing HSS functionality
