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Information on EC 2.6.1.99 - L-tryptophan-pyruvate aminotransferase and Organism(s) Arabidopsis thaliana and UniProt Accession Q9S7N2
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2.6.1.99 L-tryptophan-pyruvate aminotransferaseIUBMB Comments
This plant enzyme, along with EC 1.14.13.168, indole-3-pyruvate monooxygenase, is responsible for the biosynthesis of the plant hormone indole-3-acetate from L-tryptophan.
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Word Map
- 2.6.1.99
- auxin
-
indole-3-acetic
- iaa
-
yucca
- indole-3-pyruvate
- monooxygenases
- flavin
- aminotransferases
- trp
- meristem
- maize
-
shade
-
gravitropism
-
pin-formed1
-
trp-dependent
The taxonomic range for the selected organisms is: Arabidopsis thaliana
The enzyme appears in selected viruses and cellular organisms
The enzyme appears in selected viruses and cellular organisms
Synonyms
tryptophan aminotransferase of arabidopsis, tryptophan aminotransferase of arabidopsis1, 
more
topSYNONYM 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
TAA1
-
-
-
-
vl2
-
-
-
-
SYSTEMATIC NAME
IUBMB Comments
L-tryptophan:pyruvate aminotransferase
This plant enzyme, along with EC 1.14.13.168, indole-3-pyruvate monooxygenase, is responsible for the biosynthesis of the plant hormone indole-3-acetate from L-tryptophan.
SUBSTRATE
PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
(Substrate)
LITERATURE
(Substrate)
(Substrate)
COMMENTARY
(Product)
(Product)
LITERATURE
(Product)
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
r=reversible
ir=irreversible
?=not specified
L-isoleucine + indole-3-pyruvic acid
3-methyl-2-oxopentanoate + L-tryptophan
1% of the activity with L-methionine
-
-
?
L-leucine + indole-3-pyruvic acid
2-oxo-4-methylpentanoate + L-tryptophan
1% of the activity with L-methionine
-
-
?
L-methionine + indole-3-pyruvic acid
2-oxo-4-methylthiobutanoate + L-tryptophan
most catalytically preferred amino donor. No reverse VAS1 activity detected
-
-
ir
L-phenylalanine + indole-3-pyruvic acid
phenylpyruvate + L-tryptophan
21% of the activity with L-methionine
-
-
?
L-tyrosine + indole-3-pyruvic acid
3-(4-hydroxyphenyl)-2-oxopropanoate + L-tryptophan
1% of the activity with L-methionine
-
-
?
L-valine + indole-3-pyruvic acid
3-methyl-2-oxobutanoate + L-tryptophan
1% of the activity with L-methionine
-
-
?
L-tryptophan + pyruvate
indole-3-pyruvate + L-alanine
-
-
-
?
L-tryptophan + pyruvate
indole-3-pyruvate + L-alanine
SAV3 is specific for L-Trp
-
-
?
L-tryptophan + pyruvate
indole-3-pyruvate + L-alanine
L-Trp is the preferred substrate
-
-
?
additional information
?
-
L-kynurenine is an alternate substrate competing with L-tryptophan
-
-
?
additional information
?
-
SAV3 also uses L-Phe, Tyr, Leu, Ala, Met and Gln as substrates in vitro
-
-
?
NATURAL SUBSTRATE
NATURAL PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
(Substrate)
LITERATURE
(Substrate)
(Substrate)
COMMENTARY
(Product)
(Product)
LITERATURE
(Product)
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
r=reversible
ir=irreversible
?=not specified
L-tryptophan + pyruvate
indole-3-pyruvate + L-alanine
-
-
-
?
L-tryptophan + pyruvate
indole-3-pyruvate + L-alanine
SAV3 is specific for L-Trp
-
-
?
COFACTOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
(2S)-2-(aminooxy)-3-(naphthalen-2-yl)propanoic acid
competitive. Arabidopsis thaliana seedlings treated with the compound show typical auxin-deficient phenotypes, which are reversed by exogenous indole-3-acetic acid
L-alpha-aminooxy-phenylpropionic acid
target compound for inhibitor synthesis
additional information
synthesis of inhibitors based on L-alpha-aminooxy-phenylpropionic acid. The aminooxy and carboxy groups of the compound are essential for inhibition of TAA1 in vitro. Inhibitory activity of the compounds is correlated with their binding energy with TAA1. The active compounds reduce the endogenous indole-3-acetic acid content upon application to Arabidopsis thaiana seedlings
-
L-kynurenine
an alternate substrate, competitively inhibits TAA1/TAR activity, and Kyn treatment mimicks the loss of TAA1/TAR functions. L-kynurenine application represses activity and nuclear accumulation of the EIN3 transcription factor in roots. L-kynurenine effectively and selectively binds to the substrate pocket of TAA1/TAR proteins but not to those of other families of aminotransferases, computational docking and molecular modeling, overview
Ki VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
0.01152
L-kynurenine
inhibition of TAA1, competitive versus L-Tryp, pH not specificied in the publication, 55°C
IC50 VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
55
ORGANISM
COMMENTARY
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
SOURCE
additional information
SAV3 has a localized and dynamic expression pattern
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY
GeneOntology No.
LITERATURE
SOURCE
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
evolution
TAA1 encodes a member of a small family of aminotransferases with strong sequence similarity to C-S Lyases
malfunction
metabolism
physiological function
malfunction
-
taa mutants are partially indole-3-pyruvate-deficient, indicating that TAAs are responsible for converting tryptophan to indole-3-pyruvate. Inactivation of TAA1/TIR2 causes root resistance to the auxin transport inhibitor naphthylphthalamic acid
metabolism
-
tryptophan aminotransferase of Arabidopsis thaliana, TAA, and YUCCA work in the same pathway and that YUC is downstream of TAA. The TAA family of amino transferases converts tryptophan to indole-3-pyruvate, and the YUC family of flavin monooxygenases participates in converting IPA to indole-3-acetic acid, the main auxin in plants
physiological function
in a loss-of-function mutant, levels of the phytohormone auxin and the ethylene precursor 1-aminocyclopropane-1-carboxylate are simultaneously increased. VAS1 overexpression reduces plant stature and seed set, and these plants accumulate less auxin than wild-type under shade. VAS1 serves key roles in coordinating the levels of these two vital hormones. VAS1 and tryptophan aminotransferases Sav3 catalyze opposing reactions with respect to 3-IPA formation. In response to shade, Vas1/Sav3 double mutant plants have longer hypocotyls and petioles than sav3 single mutants. When grown in continuous white light, Vas1 or Vas1/Sav3 mutant seedlings display elongated hypocotyls and petioles, with increased leaf hyponasty, decreased leaf area
additional information
malfunction
L-kynurenine, being an alternate substrate, competitively inhibits TAA1/TAR activity, and Kyn treatment mimicks the loss of TAA1/TAR functions
malfunction
SAV3 mutants are unable to elongate in simulated shade light, phenotypes, overview. Other indole acetic acid biosynthetic pathways cannot compensate for the loss of the SAV3-dependent pathway. sav3 mutants have reduced auxin levels and a diminished auxin response, and sav3 mutants exhibit shorter hypocotyls than WT when grown in simulated shade and partially suppress the constitutive shade avoidance phenotype of a phyB null mutant, sav3-1 plants are shorter and have reduced leaf hyponasty as compared to wild-type plants. The sav3-1 mutant fails to induce shade avoidance syndrome, SAS, in a controlled environment typically used to detect PHYB-mediated SAS responses in light-grown plants
malfunction
significantly lower levels of free for indole 3-acetic acid are detected in the single wei8-2 as well as in the double wei8-2 tar2-1 mutants
malfunction
the ethylene defects of wei8 are dramatically enhanced in the wei8 tar2 double mutants that display a nearly complete lack of response to ACC in roots
metabolism
gene wei8 encodes a long-anticipated tryptophan aminotransferase, TAA1, in the essential indole-3-pyruvic acid branch of the auxin biosynthetic pathway, a link between local auxin production, tissue-specific ethylene effects, and organ development exists. TAA1 and TAR2 have overlapping roles in the ethylene response, overview
metabolism
the TAA family produces indole-3-pyruvic acid, and the YUC family functions in the conversion of indole-3-pyruvic acid to indole 3-acetic acid in Arabidopsis thaliana
metabolism
the three gene families, cytochrome P450 79B2/B3, YUCCA or YUC, and tryptophan aminotransferase of Arabidopsis 1/tryptopan aminotransferase related, i.e. TAA1/TAR, in the production of this hormone in the reference plant Arabidopsis thaliana. Each of these three gene families is believed to represent independent routes of auxin biosynthesis. TAA1/TARs and YUCs function in a common linear biosynthetic pathway that is genetically distinct from the CYP79B2/B3 route. In the redefined TAA1-YUC auxin biosynthetic pathway, TAA1/TARs are required for the production of indole-3-pyruvic acid from Trp, whereas YUCs are likely to function downstream, function of TAA1 and TARs is required for indole 3-acetic acid production via YUCs. Enzymatic reactions involved in indole-3-acetic acid production via indole-3-pyruvic acid, overview. The CYP79B2/B3 function is not required for YUC1-mediated auxin production
metabolism
tryptophan aminotransferase of Arabidopsis 1 and tryptopan aminotransferase related, i.e. TAA1 and TAR, are the key enzymes in the indole-3-pyruvic acid pathway of auxin biosynthesis
physiological function
gene wei8 encodes a long-anticipated tryptophan aminotransferase, TAA1, in the essential indole-3-pyruvic acid branch of the auxin biosynthetic pathway, a link between local auxin production, tissue-specific ethylene effects, and organ development exists. The IPA route of auxin production is key to generating robust auxin gradients in response to environmental and developmental cues. Proper gynoecium development requires TAA1 and TAR2 function
physiological function
SAV3 is an L-Trp aminotransferase involved in indole 3-acetic acid biosynthesis. SAV3 catalyzes the formation of indole-3-pyruvic acid from L-tryptophan as first step in an auxin biosynthetic pathway. Feedback regulation on SAV3 expression by shade
additional information
if TAA1/TARs and YUCs work together to produce indole 3-acetic acid, blocking the in vivo activity of TAA1/TARs with L-kynurenine suppresses the high-auxin phenotypes of YUC1ox plants
additional information
SAV3 in silico docking using the crystal structure obtained from SAV3 crystals soaked in L-Phe and co-crystallized with pyridoxal 5'-phosphate, for analyzing substrate and cofactor pecificities, overview
additional information
-
taa mutants show phenotypes including defects in shade avoidance, root resistance to ethylene and N-1-naphthylphthalamic acid, the phenotypes are phenocopied by inactivating YUC genes, overview
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION
The reliability class of the localization prediction ranges from 1 (very reliable) to 5 (not reliable).
The reliability class of the localization prediction ranges from 1 (very reliable) to 5 (not reliable). TAA1_ARATH
391
0
44801
Swiss-Prot
other Location (Reliability: 2)
SUBUNIT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
additional information
SAV3 contains a C-terminal alliinase/aminotransferase domain
CRYSTALLIZATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
molecular docking of inhibitors (2S)-2-(aminooxy)-3-(naphthalen-2-yl)propanoic acid and L-alpha-aminooxy-phenylpropionic acid
PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
K217A
the TAA1 mutant shows a defect in pyridoxal 5'-phosphate binding
additional information
additional information
construction of wei8 knockout mutants and of wei8-1 and tar2-1 mutants. If TAA1/TARs and YUCs work together to produce indole 3-acetic acid, blocking the in vivo activity of TAA1/TARs with L-kynurenine suppresses the high-auxin phenotypes of YUC1ox plants. The plants expressing the YUC1 cDNA under the control of the TAA1 regulatory sequences display a much stronger root phenotype, characterized by an extremely short root length both in light- and dark-grown seedlings. Significantly lower levels of free for indole 3-acetic acid are detected in the single wei8-2 as well as in the double wei8-2 tar2-1 mutants
additional information
generation of estradiol-inducible wei8-1 tar2-1 from wei8-1/- tar2-1/+, and wei8-1 tar2-2 from wei8-1/- tar2-2/+ mutants. TAA1 overexpression plants in Arabdopsis thaliana wild-type (TAA1ox) and yuc1D (TAA1ox yuc1D), respectively. TAA1 overexpressing plants do not show apparent phenotypes relative to vector control plants
additional information
phenotypes of multiple mutant combinations, strong ethylene defects of the wei8 tar2 roots and the typical ethylene-triggered differential growth of apical hooks is also blocked in wei8 tar2, wei8 tar2 mutants have reduced levels of auxin
additional information
-
construction of taa mutants showing phenotypes including defects in shade avoidance, root resistance to ethylene and N-1-naphthylphthalamic acid, the phenotypess are phenocopied by inactivating YUC genes, overview. Overexpression of YUC1 partially suppresses the shade avoidance defects of taa1 and the sterile phenotypes of the weak but not the strong taa mutants. The auxin overproduction phenotypes of YUC overexpression lines are dependent on active TAA genes. Construcction of wei8 tar2 mutants, phenotypes, overview
CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
expression of GST-TAA1 in Escherichia coli strain BL21 Star (DE3) pLysS
gene sav3, DNA and amino acid sequence deterination and analysis, SAV3 has a localized and dynamic expression pattern
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Tao, Y.; Ferrer, J.L.; Ljung, K.; Pojer, F.; Hong, F.; Long, J.A.; Li, L.; Moreno, J.E.; Bowman, M.E.; Ivans, L.J.; Cheng, Y.; Lim, J.; Zhao, Y.; Ballare, C.L.; Sandberg, G.; Noel, J.P.; Chory, J.
Rapid synthesis of auxin via a new tryptophan-dependent pathway is required for shade avoidance in plants
Cell
133
164-176
2008
Arabidopsis thaliana (Q9S7N2), Arabidopsis thaliana Col-0 (Q9S7N2)
Stepanova, A.N.; Robertson-Hoyt, J.; Yun, J.; Benavente, L.M.; Xie, D.Y.; Dolezal, K.; Schlereth, A.; Juergens, G.; Alonso, J.M.
TAA1-mediated auxin biosynthesis is essential for hormone crosstalk and plant development
Cell
133
177-191
2008
Arabidopsis thaliana (Q9S7N2), Arabidopsis thaliana Col-0 (Q9S7N2)
He, W.; Brumos, J.; Li, H.; Ji, Y.; Ke, M.; Gong, X.; Zeng, Q.; Li, W.; Zhang, X.; An, F.; Wen, X.; Li, P.; Chu, J.; Sun, X.; Yan, C.; Yan, N.; Xie, D.Y.; Raikhel, N.; Yang, Z.; Stepanova, A.N.; Alonso, J.M.; Guo, H.
A small-molecule screen identifies L-kynurenine as a competitive inhibitor of TAA1/TAR activity in ethylene-directed auxin biosynthesis and root growth in Arabidopsis
Plant Cell
23
3944-3960
2011
Arabidopsis thaliana (Q9S7N2), Arabidopsis thaliana Col-0 (Q9S7N2)
Stepanova, A.; Yun, J.; Robles, L.; Novak, O.; He, W.; Guo, H.; Ljung, K.; Alonso, J.
The Arabidopsis YUCCA1 flavin monooxygenase functions in the indole-3-pyruvic acid branch of auxin biosynthesis
Plant Cell
23
3961-3973
2011
Arabidopsis thaliana (Q9S7N2), Arabidopsis thaliana Col-0 (Q9S7N2)
Mashiguchi, K.; Tanaka, K.; Sakai, T.; Sugawara, S.; Kawaide, H.; Natsume, M.; Hanada, A.; Yaeno, T.; Shirasu, K.; Yao, H.; McSteen, P.; Zhao, Y.; Hayashi, K.; Kamiya, Y.; Kasahara, H.
The main auxin biosynthesis pathway in Arabidopsis
Proc. Natl. Acad. Sci. USA
108
18512-18517
2011
Arabidopsis thaliana (Q9S7N2)
Won, C.; Shen, X.; Mashiguchi, K.; Zheng, Z.; Dai, X.; Cheng, Y.; Kasahara, H.; Kamiya, Y.; Chory, J.; Zhao, Y.
Conversion of tryptophan to indole-3-acetic acid by TRYPTOPHAN AMINOTRANSFERASES OF ARABIDOPSIS and YUCCAs in Arabidopsis
Proc. Natl. Acad. Sci. USA
108
18518-18523
2011
Arabidopsis thaliana
Zheng, Z.; Guo, Y.; Novak, O.; Dai, X.; Zhao, Y.; Ljung, K.; Noel, J.; Chory, J.
Coordination of auxin and ethylene biosynthesis by the aminotransferase VAS1
Nat. Chem. Biol.
9
244-246
2013
Arabidopsis thaliana (Q9C969)
Narukawa-Nara, M.; Nakamura, A.; Kikuzato, K.; Kakei, Y.; Sato, A.; Mitani, Y.; Yamasaki-Kokudo, Y.; Ishii, T.; Hayashi, K.I.; Asami, T.; Ogura, T.; Yoshida, S.; Fujioka, S.; Kamakura, T.; Kawatsu, T.; Tachikawa, M.; Soeno, K.; Shimada, Y.
Aminooxy-naphthylpropionic acid and its derivatives are inhibitors of auxin biosynthesis targeting L-tryptophan aminotransferase: structure-activity relationships
Plant J.
87
245-257
2016
Arabidopsis thaliana (Q9S7N2)
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