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Literature summary for 4.4.1.16 extracted from

  • Chocat, P.; Esaki, N.; Tanizawa, K.; Nakamura, T.; Tanaka, H.; Soda, K.
    Purification and characterization of selenocysteine beta-lyase from Citrobacter freundii (1985), J. Bacteriol., 163, 669-676.
    View publication on PubMedView publication on EuropePMC

Activating Compound

Activating Compound Comment Organism Structure
alpha-Keto acids restore activity during reaction Citrobacter freundii

General Stability

General Stability Organism
labile during purification, 0.1% 2-mercaptoethanol, 1 mM dithiothreitol or 1 M sucrose stabilizes activity Citrobacter freundii

Inhibitors

Inhibitors Comment Organism Structure
beta-chloro-L-alanine irreversible Citrobacter freundii
Hg2+
-
Citrobacter freundii
iodoacetamide 1 mM, complete inactivation within 3 h Citrobacter freundii
iodoacetic acid 1 mM, complete inactivation within 3 h Citrobacter freundii
L-cysteine competitive Citrobacter freundii
L-cysteine methyl ester competitive Citrobacter freundii
N-ethylmaleimide 1 mM, complete inactivation within 3 h Citrobacter freundii
NaBH4 irreversible Citrobacter freundii
Ni2+
-
Citrobacter freundii
Pb2+
-
Citrobacter freundii
Zn2+
-
Citrobacter freundii

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.95
-
L-selenocysteine pH 7.2 Citrobacter freundii
3.1
-
beta-chloro-L-alanine pH 7.2 Citrobacter freundii

Localization

Localization Comment Organism GeneOntology No. Textmining
cytoplasm
-
Citrobacter freundii 5737
-

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
63000
-
HPLC gel filtration Citrobacter freundii
64000
-
SDS-PAGE Citrobacter freundii

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
L-selenocysteine + reduced acceptor Citrobacter freundii
-
selenide + L-alanine + acceptor
-
?

Organism

Organism UniProt Comment Textmining
Citrobacter freundii
-
-
-

Purification (Commentary)

Purification (Comment) Organism
-
Citrobacter freundii

Storage Stability

Storage Stability Organism
-20°C, 1 month, 60% loss of activity Citrobacter freundii

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
beta-chloro-L-alanine alpha,beta elimination, irreversible inactivation of enzyme during the course of reaction Citrobacter freundii NH3 + pyruvate + chloride
-
?
L-selenocysteine + reduced acceptor
-
Citrobacter freundii selenide + L-alanine + acceptor
-
?
L-selenocysteine + reduced acceptor strictly specific, no activity with D-isomer, enzyme is inativated during course of reaction, inactivation can be prevented by addition of alpha-keto acids Citrobacter freundii selenide + L-alanine + acceptor formation of H2Se by nonenzymatic reduction of elemental selenium in presence of dithiothreitol ?
L-selenocysteine + reduced acceptor enzyme bound pyridoxal 5'-phosphate serves as acceptor Citrobacter freundii selenide + L-alanine + acceptor formation of H2Se by nonenzymatic reduction of elemental selenium in presence of dithiothreitol ?

Subunits

Subunits Comment Organism
monomer 1 * 64000, SDS-PAGE Citrobacter freundii

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7
-
-
Citrobacter freundii

pH Range

pH Minimum pH Maximum Comment Organism
5.5 9
-
Citrobacter freundii

Cofactor

Cofactor Comment Organism Structure
pyridoxal 5'-phosphate required Citrobacter freundii
pyridoxal 5'-phosphate 1 mol bound per mol enzyme (subunit) Citrobacter freundii

Ki Value [mM]

Ki Value [mM] Ki Value maximum [mM] Inhibitor Comment Organism Structure
0.6
-
L-cysteine methyl ester pH 7.2 Citrobacter freundii
0.65
-
L-cysteine pH 7.2 Citrobacter freundii
2.5
-
beta-chloro-L-alanine pH 7.2 Citrobacter freundii