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Information on EC 5.1.1.15 - 2-aminohexano-6-lactam racemase and Organism(s) Achromobacter obae and UniProt Accession Q7M181
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5.1.1.15 2-aminohexano-6-lactam racemaseIUBMB Comments
Contains pyridoxal 5'-phosphate. Also racemises 2-aminopentano-5-lactam (alpha-amino-delta-valerolactam) and 2-amino-4-thiahexano-6-lactam (where S replaces CH2 of C-4). It does not catalyse the racemisation of alpha-amino acids but has some transaminase activity with them.
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Word Map
- 5.1.1.15
- synthesis
- amide
-
racemization
- d-aminopeptidase
- 5'-phosphate
-
ochrobactrum
- pyridoxal
- anthropi
The taxonomic range for the selected organisms is: Achromobacter obae
The enzyme appears in selected viruses and cellular organisms
The enzyme appears in selected viruses and cellular organisms
Synonyms
alpha-amino-epsilon-caprolactam racemase, aminocaprolactam racemase, 
more
topSYNONYM 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
ACL racemase
alpha-Amino-delta-valerolactam racemase
-
-
-
-
alpha-Amino-epsilon-caprolactam racemase
Aminocaprolactam racemase
-
-
-
-
Racemase, alpha-amino-epsilon-caprolactam
-
-
-
-
Racemase, alpha-amino-epsilon-caprolactam (Achromobacter obae reduced)
-
-
-
-
additional information
ACL racemase
-
-
-
-
alpha-Amino-epsilon-caprolactam racemase
-
-
-
-
REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT
LITERATURE
(S)-2-aminohexano-6-lactam = (R)-2-aminohexano-6-lactam
the racemization of ACL racemase proceeds via a two-base mechanism
(S)-2-aminohexano-6-lactam = (R)-2-aminohexano-6-lactam
single base mechanism
-
(S)-2-aminohexano-6-lactam = (R)-2-aminohexano-6-lactam
D- and L-amino acids are produced from L- and D-amino acid amides by D-aminopeptidase from Ochrobactrum anthropi C1-38 and L-amino acid amidase from Pseudomonas azotoformans IAM 1603, respectively, in the presence of alpha-amino-epsilon-caprolactam racemase from Achromobacter obae. Substrate: L-alanine amide, product: D-alanine (100% yield), substrate: L-2-aminobutyric amide, product: D-2-aminobutyric acid (100% yield), substrate: L-serine amide, product: D-serine (94% yield), substrate: L-methionine amide, product: D-methionine (100% yield), substrate: D-alanine amide, product: L-alanine (100% yield), substrate: D-leucine amide, product: L-leucine (100% yield), substrate: D-methionine amide, product: L-methionine (100% yield)
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REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
isomerization
-
-
-
-
SYSTEMATIC NAME
IUBMB Comments
2-aminohexano-6-lactam racemase
Contains pyridoxal 5'-phosphate. Also racemises 2-aminopentano-5-lactam (alpha-amino-delta-valerolactam) and 2-amino-4-thiahexano-6-lactam (where S replaces CH2 of C-4). It does not catalyse the racemisation of alpha-amino acids but has some transaminase activity with them.
CAS REGISTRY NUMBER
COMMENTARY
120669-89-8
racemase, alpha-amino-epsilon-caprolactam (Achromobacter obae reduced)
52652-64-9
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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-alpha-Amino-epsilon-caprolactam
D-alpha-Amino-epsilon-caprolactam
-
-
-
r
L-alpha-Amino-beta-thio-epsilon-caprolactam
D-alpha-Amino-beta-thio-epsilon-caprolactam
-
racemized more than 3times faster and binds about 4fold stronger to the enzyme than L-alpha-amino-epsilon-caprolactam
-
-
?
L-alpha-Amino-delta-valerolactam
D-alpha-Amino-delta-valerolactam
-
-
-
?
D-2-aminohexano-6-lactam
L-2-aminohexano-6-lactam
preferred substrate
-
-
r
L-2-aminohexano-6-lactam
D-2-aminohexano-6-lactam
high activity
-
-
r
L-alpha-Amino-epsilon-caprolactam
D-alpha-Amino-epsilon-caprolactam
-
-
-
?
L-alpha-Amino-epsilon-caprolactam
D-alpha-Amino-epsilon-caprolactam
-
-
-
?
L-alpha-Amino-epsilon-caprolactam
D-alpha-Amino-epsilon-caprolactam
-
-
-
?
L-alpha-Amino-epsilon-caprolactam
D-alpha-Amino-epsilon-caprolactam
-
-
-
?
L-alpha-Amino-epsilon-caprolactam
D-alpha-Amino-epsilon-caprolactam
-
-
-
?
L-alpha-Amino-epsilon-caprolactam
D-alpha-Amino-epsilon-caprolactam
-
-
-
-
?
L-alpha-Amino-epsilon-caprolactam
D-alpha-Amino-epsilon-caprolactam
-
r
-
?
L-alpha-Amino-epsilon-caprolactam
D-alpha-Amino-epsilon-caprolactam
-
r
-
?
additional information
?
-
The enzyme acts on a broad range of amino acid amides, particularly unbranched amino acid amides including L-alanine amide and L-serine amide. No activity with L-tyrosine amide
-
-
?
additional information
?
-
the enzyme is also active on L-alanine, L-alanine amide, L-serine amide, L-valine amide, L-methionine amide, L-phenylalanine amide, L-leucine amide, and L-phenylglycine amide, and not active on L-tyrosine amide, cf. EC 5.1.1.10
-
-
?
additional information
?
-
-
the enzyme catalyzes alpha-proton exchange of the substrate with deuterium during racemization in deuterium oxide
-
-
?
additional information
?
-
-
no racemization activity is observed with dipeptides or amino acid derivatives, such as L-Ala-D-Ala, D-Ala-L-Ala, L-alanylglycine, L-phenylglycine, or L-alanine methylester
-
-
?
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-alpha-Amino-epsilon-caprolactam
D-alpha-Amino-epsilon-caprolactam
-
-
-
r
COFACTOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
pyridoxal 5'-phosphate
PLP, the enzyme is a fold-type I PLP-dependent enzyme
pyridoxal 5'-phosphate
-
enzyme contains 1 mol of pyridoxal 5'-phosphate per mol of enzyme. Km: 0.00021 mM
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
L-alpha-Amino-delta-valerolactam
-
inactivation is due to conversion of the enzyme-bound pyridoxal 5'-phosphate into pyridoxamine 5'-phosphate by transamination with L-alpha-amino-delta-valerolactam
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
0.06
purified recombinant enzyme, substrate L-valine amide, pH 7.5, 30°C
0.1
purified recombinant enzyme, substrate L-phenylglycine, pH 7.5, 30°C
0.2
purified recombinant enzyme, substrate L-phenylalanine, pH 7.5, 30°C
0.8
purified recombinant enzyme, substrate L-methionine amide, pH 7.5, 30°C
1.8
purified recombinant enzyme, substrate L-leucine amide, pH 7.5, 30°C
16
purified recombinant enzyme, substrate L-serine amide, pH 7.5, 30°C
16.7
purified recombinant enzyme, substrate L-alanine amide, pH 7.5, 30°C
443
627
additional information
443
purified enzyme, substrate L-2-aminohexano-6-lactam, pH 7.0, 30°C
443
purified recombinant enzyme, substrate L-aspartate, pH 7.5, 30°C
627
purified enzyme, substrate D-2-aminohexano-6-lactam, pH 7.0, 30°C
627
purified recombinant enzyme, substrate D-aspartate, pH 7.5, 30°C
additional information
-
the effect of the concentration of L-alanine amide on the racemization reaction catalyzed by ACL racemase is investigated. Formation of D-alanine amide increases when the concentration of L-alanine amide is increased from 0.6 M to 1.2 M, indicating that the enzyme activity is not inhibited by the high substrate concentration
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
8.8
pH RANGE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
6 - 8
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pH 6.0: about 60% of maximal activity, pH 8.0: about 50% of maximal activity, L-alpha-amino-delta-valerolactam
6 - 9.5
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pH 6.0: about 40% of maximal activity, pH 9.5: about 60% of maximal activity, L-alpha-amino-beta-thio-epsilon-caprolactam
6.5 - 9.2
-
the effect of pH on D- or L-alanine production from L- or D-alanine amide with D-aminopeptidase or L-Aminoacid amide hydrolase in the presence of ACL racemase is investigated. Racemization is performed by ACL racemase at pH values of 6.5 to 9.2, and the maximum rate of conversion is found at pH 7.5 and at a temperature of around 45°C
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
ORGANISM
COMMENTARY
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY
GeneOntology No.
LITERATURE
SOURCE
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
evolution
the enzyme belongs to the fold-type I PLP-dependent enzyme family
malfunction
the mutation of either Asp210 or Lys267 to alanine abolish the racemization activity for 2-aminohexano-6-lactam
additional information
analysis of the structure-function relationship, overview. Lys241 is a key amino acid residue, active site structure of ACL racemase. The substrate binding site is typically located between Trp49 and Tyr137. Lys241 Nepsilon is considered to be important for recognizing the carbonyl O of the substrate. Lys241 also forms a salt bridge with Glu396. Asp210 and Lys267 are two plausible acid/base catalytic candidate residues, situated on the re and si faces of the pyridoxal 5'-phosphate ring, respectively. The racemization of ACL racemase proceeds via a two-base mechanism
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). PDB
SCOP
CATH
UNIPROT
ORGANISM
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
SUBUNIT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
CRYSTALLIZATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
at 20°C using the hanging-drop vapor diffusion method, crystal structures of native and epsilon-caprolactam complexed ACLR are solved at 2.21 and 2.40 Å indicating the catalytic residue as Tyr137
pH STABILITY
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
GENERAL STABILITY
ORGANISM
UNIPROT
LITERATURE
freezing inactivates, particularly in dilute solution of less than 1 mg/ml
-
STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
-20°C, 0.25 M sucrose, 10 mM potassium phosphate buffer, pH 7.3, 0.02 mM pyridoxal 5'-phosphate, 0.01% 2-mercaptoethanol, protein concentration: more than 0.3%, stable for at least 6 months
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-20°C, 0.25 M sucrose, enzyme concentration above 3 mg protein/ml, stable for at least 6 months
-
20°C, 0.25 M sucrose, enzyme retains approximately 90% of its initial activity after storage for 4 months
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PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
recombinant His-tagged enzyme 27.9fold from Escherichia coli strain BL21(DE3) by heat treatment, nickel affinity chromatography, and dialysis
recombinant His-tagged enzyme from Escherichia coli strain BL21 by nickel affinity chromatography and dialysis
using Ni Sepharose highperformance (Amersham) and anion-exchange chromatography (HiTrapQFF)
CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
gene ACLR, sequence comparisons, recombinant expression of codon-optimized His-tagged enzyme in Escherichia coli strain BL21, subcloning in Escherichia coli strain JM109
gene CSE45_2055, sequence comparisons, recombinant expression of codon-optimized His-tagged enzyme in Escherichia coli strain BL21(DE3), subcloning in Escherichia coli strain JM109
ACL racemase from Achromobacter obae is expressed in Escherichia coli, 300 U/liter culture
-
APPLICATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
synthesis
the enzyme might be useful for applications in dynamic kinetic resolution for D- or L-amino acid production
synthesis
synthesis
-
Achromobacter obae which produces alpha-amino-epsilon-caprolactam racemase, is utilized in industry to produce L-Lys from DL-alpha-amino-epsilon-caprolactam with a high yield in the presence of Cryptococcus laurentii, an L-alpha-amino-epsilon caprolactamase producing yeast
synthesis
-
production of DL-alpha-amino-beta-caprolactam as nutrient and food supplement
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Ahmed, S.A.; Esaki, N.; Tanaka, H.; Soda, K.
Mechanism of alpha-amino-epsilon-caprolactam racemase reaction
Biochemistry
25
385-388
1986
Achromobacter obae
Ahmed, S.A.; Esaki, N.; Tanaka, H.; Soda, K.
L-alpha-Amino-beta-thio-epsilon-caprolactam, a new sulfur-containing substrate for alpha-amino-epsilon-caprolactam racemase
FEBS Lett.
174
76-79
1984
Achromobacter obae
-
Ahmed, S.A.; Esaki, N.; Soda, K.
Purification and properties of alpha-amino-epsilon-caprolactam racemase from Achromobacter obae
FEBS Lett.
150
370-374
1982
Achromobacter obae, Achromobacter obae FERM-P776
Ahmed, S.A.; Esaki, N.; Tanaka, H.; Soda, K.
Mechanism of inactivation of alpha-amino-epsilon-caprolactam racemase by alpha-amino-delta-valerolactam
Agric. Biol. Chem.
49
2991-2997
1985
Achromobacter obae
-
Ahmed, S.A.; Esaki, N.; Tanaka, H.; Soda, K.
Properties of alpha-amino-epsilon-caprolactam racemase from Achromobacter obae
Agric. Biol. Chem.
47
1887-1893
1983
Achromobacter obae
-
Ahmed, S.A.; Esaki, N.; Tanaka, H.; Soda, K.
Racemization of alpha-amino-delta-valerolactam catalyzed by alpha-amino-epsilon-caprolactam racemase from Achromobacter obae
Agric. Biol. Chem.
47
1149-1150
1983
Achromobacter obae
-
Fukumura, T.
Partial purification and some properties of alpha-amino-epsilon-caprolactam-racemizing enzyme from Achromobacter obae
Agric. Biol. Chem.
41
1509-1510
1977
Achromobacter obae
-
Crosby, J.
Synthesis of optically active compounds: A large scale perspective
Tetrahedron
47
4789-4846
1991
Achromobacter obae
-
Asano, Y.; Yamaguchi, S.
Dynamic kinetic resolution of amino acid amide catalyzed by D-aminopeptidase and alpha-amino-epsilon-caprolactam racemase
J. Am. Chem. Soc.
127
7696-7697
2005
Achromobacter obae
Yamaguchi, S.; Komeda, H.; Asano, Y.
New enzymatic method of chiral amino acid synthesis by dynamic kinetic resolution of amino acid amides: use of stereoselective amino acid amidases in the presence of alpha-amino-epsilon-caprolactam racemase
Appl. Environ. Microbiol.
73
5370-5373
2007
Achromobacter obae
Okazaki, S.; Suzuki, A.; Mizushima, T.; Kawano, T.; Komeda, H.; Asano, Y.; Yamane, T.
The novel structure of a pyridoxal 5-phosphate-dependent fold-type I racemase, alpha-amino-epsilon-caprolactam racemase from Achromobacter obae
Biochemistry
48
941-950
2009
Achromobacter obae (Q7M181), Achromobacter obae
Payoungkiattikun, W.; Okazaki, S.; Nakano, S.; Ina, A.; H-Kittikun, A.; Asano, Y.
In silico identification for alpha-amino-epsilon-caprolactam racemases by using information on the structure and function relationship
Appl. Biochem. Biotechnol.
176
1303-1314
2015
Achromobacter obae (Q7M181), Brucella anthropi, Brucella anthropi (A6X7I5), Brucella anthropi ATCC 49188 / DSM 6882 / JCM 21032 / NBRC 15819 / NCTC 12168 (A6X7I5), Brucella anthropi IA / NCBIMB41129, Citreicella sp. SE45, Glutamicibacter nicotianae, Glutamicibacter nicotianae NCIMB 41126, Janibacter sp. HTCC2649 (A3TM80), Mesorhizobium opportunistum (F7Y223), Mesorhizobium opportunistum WSM 2075 (F7Y223), Mycolicibacterium vanbaalenii (A1T974), Mycolicibacterium vanbaalenii PYR-1 (A1T974), Sinorhizobium medicae (A6UKD1), Sinorhizobium medicae WSM 419 (A6UKD1), Sinorhizobium meliloti (H0FT96), Sinorhizobium meliloti (Q92MM4), Sinorhizobium meliloti CCNWSX0020 (H0FT96)
Payoungkiattikun, W.; Okazaki, S.; Ina, A.; H-Kittikun, A.; Asano, Y.
Characterization of an alpha-amino-epsilon-caprolactam racemase with broad substrate specificity from Citreicella sp. SE45
J. Ind. Microbiol. Biotechnol.
44
677-685
2017
Achromobacter obae (Q7M181), Citreicella sp. SE45
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