Literature summary for 4.1.2.42 extracted from

Chen, Q.; Chen, X.; Cui, Y.; Ren, J.; Lu, W.; Feng, J.; Wu, Q.; Zhu, D.
A new D-threonine aldolase as a promising biocatalyst for highly stereoselective preparation of chiral aromatic beta-hydroxy-alpha-amino acids (2017), Catal. Sci. Technol., 7, 5964-5973 .

No PubMed abstract available

Application

Application	Comment	Organism
synthesis	the enzyme might be a promising biocatalyst for producing chiral aromatic beta-hydroxy-alpha-amino acids	Delftia sp.

Cloned(Commentary)

Cloned (Comment)	Organism
expressed in Escherichia coli BL21 (DE3)	Delftia sp.

General Stability

General Stability	Organism
existence of the metal ions (Mn2+) enhances the stability of the enzyme	Delftia sp.

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism	Structure
0.35	-	D-allo-threonine	pH 6.0, 50°C	Delftia sp.
0.83	-	D-threonine	pH 6.0, 50°C	Delftia sp.

Metals/Ions

Metals/Ions	Comment	Organism	Structure
MnCl2	metal ion-free enzyme solution shows no activity. Metal ions are required for the reaction. The highest activity is recovered with Mn2+	Delftia sp.

Molecular Weight [Da]

Molecular Weight [Da]	Molecular Weight Maximum [Da]	Comment	Organism
47000	-	gel filtration	Delftia sp.

Organism

Organism	UniProt	Comment	Textmining
Delftia sp.	A0A031HCH9	-	-
Delftia sp. RIT313	A0A031HCH9	-	-

Purification (Commentary)

Purification (Comment)	Organism
-	Delftia sp.

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg]	Specific Activity Maximum [µmol/min/mg]	Comment	Organism
21.3	-	pH 6.0, 50°C	Delftia sp.

Storage Stability

Storage Stability	Organism
-80°C, recombinant His-tagged enzyme remains stable for 6 months	Delftia sp.

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.
D-allo-threonine	-	Delftia sp.	glycine + acetaldehyde	-	?
D-allo-threonine	-	Delftia sp. RIT313	glycine + acetaldehyde	-	?
D-threonine	-	Delftia sp.	glycine + acetaldehyde	-	r
D-threonine	-	Delftia sp. RIT313	glycine + acetaldehyde	-	r
glycine + 2-chlorobenzaldehyde	the reaction conversion and the diastereomeric excess of the 2-substituted substrates decrease in the order of F, H, Cl, Br	Delftia sp.	D-3-(2-chlorophenyl)serine	-	r
glycine + 2-chlorobenzaldehyde	the reaction conversion and the diastereomeric excess of the 2-substituted substrates decrease in the order of F, H, Cl, Br	Delftia sp. RIT313	D-3-(2-chlorophenyl)serine	-	r
glycine + 2-fluorobenzaldehyde	the reaction conversion and the diastereomeric excess of the 2-substituted substrates decrease in the order of F, H, Cl, Br	Delftia sp.	D-3-(2-fluorophenyl)serine	-	r
glycine + 2-nitrobenzaldehyde	the reaction conversion and the diastereomeric excess of the 2-substituted substrates decrease in the order of F, H, Cl, Br	Delftia sp.	D-3-(2-nitrophenyl)serine	-	r
glycine + 3-chlorobenzaldehyde	-	Delftia sp.	D-3-(3-chlorophenyl)serine	-	r
glycine + 3-fluorobenzaldehyde	-	Delftia sp.	D-3-(3-fluorophenyl)serine	-	r
glycine + 3-nitrobenzaldehyde	-	Delftia sp.	D-3-(3-nitrophenyl)serine	-	r
glycine + 4-(methylsulfonyl)benzaldehyde	-	Delftia sp.	D-3-(4-methylsulfonylphenyl)serine	-	r
glycine + 4-fluorobenzaldehyde	-	Delftia sp.	D-3-(4-fluorophenyl)serine	-	r
glycine + 4-nitrobenzaldehyde	-	Delftia sp.	D-3-(4-nitrophenyl)serine	-	r
glycine + acetaldehyde	-	Delftia sp.	D-allothreonine	-	r
glycine + acetaldehyde	-	Delftia sp.	D-threonine	-	r
glycine + benzaldehyde	the erythro isomer is obtained as the major product when the temperature is above 15°C, and lowering the temperature result in an increase in threo isomer.Water-miscible organic solvents exert limited effect on the conversion, but greatly enhance the diastereomeric excess of the product, with 10% CH3CN giving the highest diastereomeric excess. For other organic solvents (THF, ethyl acetate, 2-methoxy-2-methylpropan, 1,4-dioxane, dichloromethane and toluene), lower stereoselectivity at the beta-carbon is observed	Delftia sp.	(2R,3S)-2-amino-3-hydroxy-3-phenylpropanoic acid + (2R,3R)-2-amino-3-hydroxy-3-phenylpropanoic acid	-	r
glycine + benzaldehyde	the erythro isomer is obtained as the major product when the temperature is above 15°C, and lowering the temperature result in an increase in threo isomer.Water-miscible organic solvents exert limited effect on the conversion, but greatly enhance the diastereomeric excess of the product, with 10% CH3CN giving the highest diastereomeric excess. For other organic solvents (THF, ethyl acetate, 2-methoxy-2-methylpropan, 1,4-dioxane, dichloromethane and toluene), lower stereoselectivity at the beta-carbon is observed	Delftia sp. RIT313	(2R,3S)-2-amino-3-hydroxy-3-phenylpropanoic acid + (2R,3R)-2-amino-3-hydroxy-3-phenylpropanoic acid	-	r
additional information	the enzyme shows high activity toward aromatic aldehydes with electron-withdrawing substituents. The substrate profiling indicates that the enzyme accepts a wider range of acceptor substrates and is more active toward aromatic aldehydes bearing electron-withdrawing groups than those with electron-donating substituents. Molecular docking studies suggest that the substituent on the benzene ring of the substrate is critical in determining the enzyme activity and stereoselectivity by affecting the interaction between the beta-OH-group of the substrate and the manganese ion	Delftia sp.	?	-	?
additional information	the enzyme shows high activity toward aromatic aldehydes with electron-withdrawing substituents. The substrate profiling indicates that the enzyme accepts a wider range of acceptor substrates and is more active toward aromatic aldehydes bearing electron-withdrawing groups than those with electron-donating substituents. Molecular docking studies suggest that the substituent on the benzene ring of the substrate is critical in determining the enzyme activity and stereoselectivity by affecting the interaction between the beta-OH-group of the substrate and the manganese ion	Delftia sp. RIT313	?	-	?

Subunits

Subunits	Comment	Organism
monomer	1 * 47000, SDS-PAGE	Delftia sp.

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
25	-	assay at	Delftia sp.
50	60	aldol addition	Delftia sp.

Temperature Stability [°C]

Temperature Stability Minimum [°C]	Temperature Stability Maximum [°C]	Comment	Organism
additional information	-	existence of the metal ions (Mn2+) enhances the thermal stability of the enzyme	Delftia sp.
25	60	the enzyme retains about 70% activity from 25°C to 60°C after it is heated for 30 min	Delftia sp.
70	-	30 min, 50% loss of activity	Delftia sp.
80	-	30 min, 70% loss of activity	Delftia sp.

Turnover Number [1/s]

Turnover Number Minimum [1/s]	Turnover Number Maximum [1/s]	Substrate	Comment	Organism	Structure
0.25	-	D-allo-threonine	pH 6.0, 50°C	Delftia sp.
0.39	-	D-threonine	pH 6.0, 50°C	Delftia sp.

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
6	-	aldol addition	Delftia sp.
8	-	retro-aldol addition	Delftia sp.

pH Range

pH Minimum	pH Maximum	Comment	Organism
5	10	pH 5.0: about 55% of maximal activity, pH 10.0: about 45% of maximal activity, aldol addition	Delftia sp.
6	9.5	pH 6.0: about 65% of maximal activity, pH 9.5: about 75% of maximal activity, retro-aldol addition	Delftia sp.

pH Stability

pH Stability	pH Stability Maximum	Comment	Organism
6	-	after being incubated at various pH values for 12 h, the enzyme retains the highest activity at pH 6.0 for both retro-aldol and aldol addition reactions	Delftia sp.

Cofactor

Cofactor	Comment	Organism	Structure
pyridoxal 5'-phosphate	dependent on	Delftia sp.

kcat/KM [mM/s]

kcat/KM Value [1/mMs^-1]	kcat/KM Value Maximum [1/mMs^-1]	Substrate	Comment	Organism	Structure
0.47	-	D-threonine	pH 6.0, 50°C	Delftia sp.
0.71	-	D-allo-threonine	pH 6.0, 50°C	Delftia sp.