1.5.3.17: non-specific polyamine oxidase
This is an abbreviated version!
For detailed information about non-specific polyamine oxidase, go to the full flat file.
Word Map on EC 1.5.3.17
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1.5.3.17
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spermidine
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back-conversion
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putrescine
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peroxisomal
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sativa
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seedling
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tetraamines
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abscisic
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anther
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pollen
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medicine
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analysis
- 1.5.3.17
- spermidine
-
back-conversion
- putrescine
- peroxisomal
- sativa
- seedling
-
tetraamines
-
abscisic
- anther
- pollen
- medicine
- analysis
Reaction
Synonyms
AtPAO2, AtPAO3, AtPAO4, AtPAO5, Bjpao1, Bjpao2, EC 1.5.3.11, Fms1, LC036642, OsPAO1, PAO, PAO1, PAO2, PAO3, PAO5, polyamine oxidase 1, SelPAO5, slr5093, T-Spm oxidase, thermospermine oxidase
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General Information
General Information on EC 1.5.3.17 - non-specific polyamine oxidase
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evolution
malfunction
metabolism
physiological function
additional information
AtPAO2-AtPAO4 form a subfamily of polyamine oxxidases different from AtPAO1, EC 1.5.3.16, overview
evolution
Plantae
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identification of four polyamine oxidase subfamilies in plants. Subfamily PAO back conversion 1 (PAObc1) is present on every lineage included in these analyses. Subfamily PAObc2 is exclusively present in vascular plants. The only terminal catabolism (TC) PAO subfamily was lost in Superasterids but it is present in all other land plants. Subfamily PAObc3 is the result of a gene duplication event preceding Angiosperm diversification, followed by a gene extinction in Monocots. Differential conserved protein motifs exist for each subfamily of plant PAOs
evolution
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AtPAO2-AtPAO4 form a subfamily of polyamine oxxidases different from AtPAO1, EC 1.5.3.16, overview
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loss-of-function mutants contain 2-fold higher thermospermine levels and exhibit delayed transition from vegetative to reproductive growth compared with that of wild-type plants
malfunction
loss-of-function of AtPAO gene results to increased NADPH-oxidase-dependent production of superoxide anions but not H2O2, which activates the mitochondrial alternative oxidase pathway (AOX). On the contrary, overexpression of AtPAO3 results in an increased but balanced production of both H2O2 and superoxide anions
malfunction
two loss-of-function atpao5 mutants and a 35S::AtPAO5 Arabidopsis transgenic line present phenotypical differences from the wild-type plants with regard to stem and root elongation, differences that are accompanied by changes in polyamine levels and the number of xylem vessels. It is shown that cytokinin treatment, which up-regulates AtPAO5 expression in roots, differentially affects protoxylem differentiation in 35S::AtPAO5, atpao5, and wild-type roots
the enzyme is involved in the polyamine back-conversion pathway, overview
metabolism
the enzyme contributes to abscisic acid mediated plant developmental processes
metabolism
residues Gln94, Tyr403 and Thr440 are predicted to be important in the active site
metabolism
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the enzyme is involved in the polyamine back-conversion pathway, overview
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pollen from mutants lacking expression of the peroxisomal-encoding AtPAO3 gene, is unable to induce the opening of the Ca2+-permeable channels in the presence of spermidine, resulting in reduced pollen tube growth and seed number. A high spermidine concentration triggers a Ca2+ influx beyond the optimal, which has adeleterious effect
physiological function
flavoprotein Fms1 catalyzes the oxidation of spermine in the biosynthetic pathway for pantothenic acid
physiological function
plant PAOs oxidize the carbon at the endo-side of the N4-nitrogen of Spd and Spm, producing 4-aminobutanal and N-(3-aminopropyl)-4-aminobutanal, respectively, in addition to 1,3-diaminopropane and H2O2, and are considered to be involved in terminal catabolism of polyamines, physiological role(s) of the polyamine catabolic pathways in plants, overview. All AtPAOs characterized are involved in a polyamine backconversion pathway
physiological function
polyaminehomeostasis, plant growth, stress response
physiological function
potential contributory function of the enzyme AtPAO2 in NO-mediated effects on root growth
physiological function
the cross-talk of the enzyme with NADPH-oxidase balances intracellular superoxide anion/H2O2 which in turn affects the cytochrome-c pathway/alternative terminal oxidase pathway
physiological function
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the enzyme functions as thermospermine oxidase. The enzyme OsPAO1 from Oryzae sativa is the functional ortholog of enzyme AtPAO5 from Arabidopsis thaliana. OsPAO1 is able to complement the growth defects of Atpao5 deletion mutants
physiological function
the enzyme has a function in abscisic acid modulating vegetative growth and in root architecture
physiological function
the enzyme is a source of H2O2 generation in Arabidopsis guard cells and plays crucial roles in stomatal movement
physiological function
the enzyme is involved in the control of Therm-Spm homeostasis. It participates in the tightly controlled interplay between auxin and cytokinins that is necessary for proper xylem differentiation
physiological function
the enzyme regulates thermospermine homeostasis through a thermospermine oxidation pathway
physiological function
isoforms Pao1 and Pao2 single mutant lines display altered responses to Pseudomonas syringae, and an increased susceptibility is found in the Pao1/Pao2 double mutant. These mutant lines show disturbed contents of ROS (H2O2 and O2- radical) and altered activities of superoxide dismutase, catalase and respiratory burst oxidase homologue enzymes both in infected and control plants
physiological function
when PAO5 is expressed in an Arabidopsis thaliana Pao5 mutant, thermospermine level decreases to almost normal values of wild type plants, and norspermidine is produced. The reduced growth phenotype of the mutant strain is cured by the expression of PAO5
physiological function
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plant PAOs oxidize the carbon at the endo-side of the N4-nitrogen of Spd and Spm, producing 4-aminobutanal and N-(3-aminopropyl)-4-aminobutanal, respectively, in addition to 1,3-diaminopropane and H2O2, and are considered to be involved in terminal catabolism of polyamines, physiological role(s) of the polyamine catabolic pathways in plants, overview. All AtPAOs characterized are involved in a polyamine backconversion pathway
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His64 hydrogen bonds to the reactive nitrogen in the polyamine substrate
additional information
the active site of Fms1 contains three amino acid residues positioned to interact with the polyamine substrate, His67, Asn195, and Asp94. These three residues form a hydrogen-bonding triad with Asn195 being the central residue. His67 is important both for interacting with the substrate and for maintaining the hydrogen bonds in the triad
additional information
the overall catalytic reactions of flavoprotein oxidases such as Fms1 can be divided into reductive and oxidative half-reactions. In the reductive half-reaction, binding of the oxidized substrate is followed by transfer of a hydride equivalent to the flavin to form reduced flavin and oxidized substrate. In the oxidative half-reaction, the reduced flavin is oxidized by molecular oxygen to form H2O2, the oxidized amine then dissociates from the enzyme. A moiety with a pKa value of 7.2-8.3 must be unprotonated for amine oxidation