Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
twitter

MetaCyc Enzyme: gibberellin 3-oxidase

Gene: GA3ox1 Accession Number: AT1G15550 (MetaCyc)

Synonyms: GA4, at1g15550, AtGA3OX1, GA 3β-hydroxylase, GA3OX, gibberellin 3β-hydroxylase

Species: Arabidopsis thaliana col

Summary:
The GA4 gene was isolated from floral apices of the ga1-2 mutant of Arabidopsis thaliana L. Heynh. This gene was shown to encode a gibberellin 3β-hydroxylase (GA3OX). The recombinant GA 3β-oxidase was expressed in Escherichia coli, the bacterial cell lysates of which was used to assess the conversion efficiency of the protein towards a number of radiolabeled gibberellins (GAs) [Williams98]. Of the various GAs tested GA9 was the preferred substrate, which is consistent with the predominance of non-13-hydroxylated GAs in Arabidopsis. GA3OX was also shown to efficiently convert GA20 and to a lesser extent GA15, GA24 and GA44 [Williams98]. Interestingly, the closed lactone form of GA15 was hydroxylated almost as efficiently as GA20 (see reaction gibberellin A15 (closed lactone form) + 2-oxoglutarate + oxygen → gibberellin A37 (closed lactone form) + succinate + CO2), while the open lactone was a poor substrate [Williams98]. In general, C19-GAs are much better substrates for GA3OX than C19-GAs.

Citations: [Talon90]

Map Position: [5,351,680 -> 5,353,189] (17.79 centisomes)

Unification Links: ArrayExpress:Q39103 , Entrez:L37126 , ModBase:Q39103 , PhylomeDB:Q39103 , Pride:Q39103 , Protein Model Portal:Q39103 , SMR:Q39103 , String:Q39103 , Swiss-Model:Q39103 , TAIR:AT1G15550 , UniProt:Q39103

Relationship Links: Entrez-Nucleotide:PART-OF:AAC37506 , InterPro:IN-FAMILY:IPR002283 , InterPro:IN-FAMILY:IPR005123 , InterPro:IN-FAMILY:IPR026992 , InterPro:IN-FAMILY:IPR027443 , Pfam:IN-FAMILY:PF03171 , Pfam:IN-FAMILY:PF14226 , Prints:IN-FAMILY:PR00682 , Prosite:IN-FAMILY:PS51471

Gene-Reaction Schematic: ?


Enzymatic reaction of: gibberellin-15(closed lactone form),2-oxoglutarate:oxygen oxidoreductase (3β-hydroxylating) (gibberellin 3-oxidase)

EC Number: 1.14.11.-

gibberellin A15 (closed lactone form) + 2-oxoglutarate + oxygen <=> gibberellin A37 (closed lactone form) + succinate + CO2

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is physiologically favored in the direction shown.


Enzymatic reaction of: (gibberellin-9),2-oxoglutarate:oxygen oxidoreductase (3β-hydroxylating) (gibberellin 3-oxidase)

EC Number: 1.14.11.-

gibberellin A9 + 2-oxoglutarate + oxygen <=> gibberellin A4 + succinate + CO2

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is physiologically favored in the direction shown.

In Pathways: superpathway of gibberellin biosynthesis , gibberellin biosynthesis I (non C-3, non C-13 hydroxylation)

Summary:
A Vmax value of 6.8 pmol.min-1.mg-1 was determined in the reaction described in [Williams98].

Kinetic Parameters:

Substrate
Km (μM)
Citations
gibberellin A9
1.0
[Williams98]


Enzymatic reaction of: (gibberellin-24),2-oxoglutarate:oxygen oxidoreductase (3β-hydroxylating) (gibberellin 3-oxidase)

EC Number: 1.14.11.-

gibberellin A24 + 2-oxoglutarate + oxygen <=> gibberellin A36 + succinate + CO2

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is physiologically favored in the direction shown.

In Pathways: superpathway of gibberellin biosynthesis , gibberellin biosynthesis I (non C-3, non C-13 hydroxylation)


Enzymatic reaction of: (gibberellin-20),2-oxoglutarate:oxygen oxidoreductase (3β-hydroxylating) (gibberellin 3-oxidase)

EC Number: 1.14.11.15

gibberellin A20 + 2-oxoglutarate + oxygen <=> gibberellin A1 + succinate + CO2

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

The reaction is physiologically favored in the direction shown.

In Pathways: superpathway of gibberellin biosynthesis , gibberellin biosynthesis III (early C-13 hydroxylation)

Summary:
A Vmax value of 2.8 pmol.min-1.mg-1 was determined in the reaction described in [Williams98].

Kinetic Parameters:

Substrate
Km (μM)
Citations
gibberellin A20
15.0
[Williams98]


Enzymatic reaction of: (gibberellin-15),2-oxoglutarate:oxygen oxidoreductase (3β-hydroxylating) (gibberellin 3-oxidase)

EC Number: 1.14.11.-

gibberellin A15 (open lactone form) + 2-oxoglutarate + oxygen <=> gibberellin A37 + succinate + CO2

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is physiologically favored in the direction shown.

In Pathways: superpathway of gibberellin biosynthesis , gibberellin biosynthesis II (early C-3 hydroxylation)


Enzymatic reaction of: (gibberellin-44),2-oxoglutarate:oxygen oxidoreductase (3β-hydroxylating) (gibberellin 3-oxidase)

EC Number: 1.14.11.-

gibberellin44 (open lactone form) + 2-oxoglutarate + H+ + oxygen <=> gibberellin A38 + succinate + CO2 + H2O

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is physiologically favored in the direction shown.

In Pathways: superpathway of gibberellin biosynthesis , gibberellin biosynthesis III (early C-13 hydroxylation)


References

Talon90: Talon M, Koornneef M, Zeevaart JA (1990). "Endogenous gibberellins in Arabidopsis thaliana and possible steps blocked in the biosynthetic pathways of the semidwarf ga4 and ga5 mutants." Proc Natl Acad Sci U S A 87(20);7983-7. PMID: 2236013

Williams98: Williams J, Phillips AL, Gaskin P, Hedden P (1998). "Function and substrate specificity of the gibberellin 3beta-hydroxylase encoded by the Arabidopsis GA4 gene." Plant Physiol 1998;117(2);559-63. PMID: 9625708


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 18.5 on Sun Nov 23, 2014, BIOCYC13B.