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Literature summary for 3.2.1.18 extracted from

  • Guo, L.; Chen, X.; Xu, L.; Xiao, M.; Lu, L.
    Enzymatic synthesis of 6-sialyllactose, a dominant sialylated human milk oligosaccharide, by a novel exo-alpha-sialidase from Bacteroides fragilis NCTC9343 (2018), Appl. Environ. Microbiol., 84, e00071-18 .
    View publication on PubMedView publication on EuropePMC
Search for more literature for 3.2.1.18

Cloned(Commentary)

Cloned (Comment) Organism
expressed in Escherichia coli BL21(DE3) cells Bacteroides fragilis

Inhibitors

Inhibitors Comment Organism Structure
Ag+
-
 Bacteroides fragilis
Ca2+
-
 Bacteroides fragilis
Co2+
-
 Bacteroides fragilis
Cu2+
-
 Bacteroides fragilis
EDTA
-
 Bacteroides fragilis
Fe2+
-
 Bacteroides fragilis
Fe3+
-
 Bacteroides fragilis
Hg2+
-
 Bacteroides fragilis
K+
-
 Bacteroides fragilis
Mn2+
-
 Bacteroides fragilis
Na+
-
 Bacteroides fragilis
NH4+
-
 Bacteroides fragilis
Zn2+
-
 Bacteroides fragilis

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.06
-
 4-methylumbelliferyl N-acetyl-alpha-D-neuraminic acid at pH 6.5 and 50°C Bacteroides fragilis
0.75
-
 sialic acid at pH 6.5 and 50°C Bacteroides fragilis

Metals/Ions

Metals/Ions Comment Organism Structure
Mg2+
-
 Bacteroides fragilis
Ni2+
-
 Bacteroides fragilis

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
113600
-
 gel filtration Bacteroides fragilis

Organism

Organism UniProt Comment Textmining
Bacteroides fragilis Q5L868
-
-
Bacteroides fragilis NCTC 9343 Q5L868
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
3'-siallyllactose + H2O
-
 Bacteroides fragilis sialic acid + lactose
-
 r
3'-siallyllactose + H2O
-
 Bacteroides fragilis NCTC 9343 sialic acid + lactose
-
 r
4-methylumbelliferyl N-acetyl-alpha-D-neuraminic acid + H2O highest activity Bacteroides fragilis ?
-
 ?
6'-sialyllactose + H2O
-
 Bacteroides fragilis sialic acid + lactose
-
 r
6'-sialyllactose + H2O
-
 Bacteroides fragilis NCTC 9343 sialic acid + lactose
-
 r
colominic acid + H2O
-
 Bacteroides fragilis ?
-
 ?
colominic acid + H2O
-
 Bacteroides fragilis NCTC 9343 ?
-
 ?
additional information the enzyme has no activities toward other substrates with beta-linkages or lacking sialic acid in the glycan moieties, including 4-methylumbelliferyl alpha- or 4-methylumbelliferyl beta-D-galactopyranoside, 4-nitrophenyl alpha- or 4-nitrophenyl beta-D-galactopyranoside, 2-nitrophenyl alpha-or 2-nitrophenyl beta-D-galactopyranoside, 3-nitrophenyl D-galactopyranoside, 4-nitrophenyl alpha- or 4-nitrophenyl beta-D-glucopyranoside, 4-nitrophenyl alpha- or 4-nitrophenyl beta-D-mannopyranoside, 4-nitrophenyl alpha-L-mannopyranoside, 4-nitrophenyl beta D-mannopyranoside, 4-nitrophenyl 2-acetylamino-2-deoxy-alpha- or 4-nitrophenyl 2-acetylamino-2-deoxy-beta-D-galactopyranoside, and 4-nitrophenyl 2-acetylamino-2-deoxy-beta-D-glucopyranoside Bacteroides fragilis ?
-
 ?
additional information the enzyme hydrolyzes alpha2-3- and alpha2-6-linked sialyllactose, as well as alpha2-8-linked disaccharides and polysaccharides, but with a preference for alpha2-8-linked saccharides over alpha2-3- and alpha2-6-linked substrates Bacteroides fragilis ?
-
 ?
additional information the enzyme has no activities toward other substrates with beta-linkages or lacking sialic acid in the glycan moieties, including 4-methylumbelliferyl alpha- or 4-methylumbelliferyl beta-D-galactopyranoside, 4-nitrophenyl alpha- or 4-nitrophenyl beta-D-galactopyranoside, 2-nitrophenyl alpha-or 2-nitrophenyl beta-D-galactopyranoside, 3-nitrophenyl D-galactopyranoside, 4-nitrophenyl alpha- or 4-nitrophenyl beta-D-glucopyranoside, 4-nitrophenyl alpha- or 4-nitrophenyl beta-D-mannopyranoside, 4-nitrophenyl alpha-L-mannopyranoside, 4-nitrophenyl beta D-mannopyranoside, 4-nitrophenyl 2-acetylamino-2-deoxy-alpha- or 4-nitrophenyl 2-acetylamino-2-deoxy-beta-D-galactopyranoside, and 4-nitrophenyl 2-acetylamino-2-deoxy-beta-D-glucopyranoside Bacteroides fragilis NCTC 9343 ?
-
 ?
additional information the enzyme hydrolyzes alpha2-3- and alpha2-6-linked sialyllactose, as well as alpha2-8-linked disaccharides and polysaccharides, but with a preference for alpha2-8-linked saccharides over alpha2-3- and alpha2-6-linked substrates Bacteroides fragilis NCTC 9343 ?
-
 ?
sialic acid + lactose the enzyme is able to transfer sialyl from sialic acid dimer or oligomer to lactose with high efficiency and strict alpha2-6 regioselectivity Bacteroides fragilis 6'-sialyllactose
-
 r

Subunits

Subunits Comment Organism
homodimer 2 * 57900, SDS-PAGE Bacteroides fragilis

Synonyms

Synonyms Comment Organism
GH33C
-
 Bacteroides fragilis

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
45
-
-
 Bacteroides fragilis

Temperature Stability [°C]

Temperature Stability Minimum [°C] Temperature Stability Maximum [°C] Comment Organism
20 40 the enzyme remains stable after 1 h at 20-40°C Bacteroides fragilis

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
283.2
-
 4-methylumbelliferyl N-acetyl-alpha-D-neuraminic acid at pH 6.5 and 50°C Bacteroides fragilis
329.6
-
 sialic acid at pH 6.5 and 50°C Bacteroides fragilis

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
6.5
-
-
 Bacteroides fragilis

pH Stability

pH Stability pH Stability Maximum Comment Organism
5 6 the enzyme shows more than 50% activity after 1 h at pH 5.0-6.0 Bacteroides fragilis

kcat/KM [mM/s]

kcat/KM Value [1/mMs-1] kcat/KM Value Maximum [1/mMs-1] Substrate Comment Organism Structure
438
-
 sialic acid at pH 6.5 and 50°C Bacteroides fragilis
4857.3
-
 4-methylumbelliferyl N-acetyl-alpha-D-neuraminic acid at pH 6.5 and 50°C Bacteroides fragilis