Literature summary for 4.2.3.1 extracted from

Curien, G.; Job, D.; Douce, R.; Dumas, R.
Allosteric activation of Arabidopsis threonine synthase by S-adenosylmethionine (1998), Biochemistry, 37, 13212-13221.

Search for more literature for 4.2.3.1

Activating Compound

Activating Compound	Comment	Organism	Structure
S-adenosylmethionine	affects both Km and Vmax by allosteric and cooperative transition of enzyme, two mol per mol enzyme, 25fold decrease of Km at 0.06 mM	Arabidopsis thaliana

Application

Application	Comment	Organism
agriculture	possible herbicide target	Arabidopsis thaliana
nutrition	interesting with respect to attempts to obtain transgenic plants with elevated levels of essential amino acids Met, Lys, Thr	Arabidopsis thaliana

Cloned(Commentary)

Cloned (Comment)	Organism
expressed in Escherichia coli	Arabidopsis thaliana

Molecular Weight [Da]

Molecular Weight [Da]	Molecular Weight Maximum [Da]	Comment	Organism
110000	-	gel filtration	Arabidopsis thaliana

Organism

Organism	UniProt	Comment	Textmining
Arabidopsis thaliana	-	-	-

Purification (Commentary)

Purification (Comment)	Organism
recombinant enzyme	Arabidopsis thaliana

Reaction

Reaction	Comment	Organism	Reaction ID
O-phospho-L-homoserine + H2O = L-threonine + phosphate	mechanism	Arabidopsis thaliana	a

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg]	Specific Activity Maximum [µmol/min/mg]	Comment	Organism
3.8	-	-	Arabidopsis thaliana

Storage Stability

Storage Stability	Organism
-80°C, Na-HEPES buffer, pH 7.5, several months, no loss of activity	Arabidopsis thaliana

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
O-phospho-L-homoserine + H2O	-	Arabidopsis thaliana	L-threonine + phosphate	-	?

Subunits

Subunits	Comment	Organism
dimer	-	Arabidopsis thaliana

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
30	-	enzyme assay at	Arabidopsis thaliana

Turnover Number [1/s]

Turnover Number Minimum [1/s]	Turnover Number Maximum [1/s]	Substrate	Comment	Organism	Structure
0.4	-	O-phosphohomoserine	without S-adenosylmethionine	Arabidopsis thaliana
3.5	-	O-phosphohomoserine	at 0.06 mM S-adenosylmethionine	Arabidopsis thaliana

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
8	-	enzyme assay at	Arabidopsis thaliana

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Release 2023.1 (January 2023)