A1A399 · BGAL_BIFAA

Function

function

Involved in the hydrolysis of transgalactooligosaccharides (TOS). Highly active towards Gal(beta1-4)Gal and Gal(beta1-4)-Gal-containing oligosaccharides. Low activity towards Gal(beta1-3)Gal, lactose and Gal(beta1-3)GalOMe. No activity towards Gal(beta1-6)Gal, Gal(beta1-4)Man, Gal(alpha1-4)Gal, Gal(alpha1-3)Gal(beta1-4)Gal, lactulose, 3'fucosyllactose, lacto-N-fucopentaose I, lacto-N-fucopentaose II, cellobiose, maltose or sucrose. No transglycosylation activity is found at high substrate concentrations (100 mg/ml) and only low transglycosylation activity at lower substrate concentrations (10 mg/ml).

Catalytic activity

  • Hydrolysis of terminal non-reducing beta-D-galactose residues in beta-D-galactosides.
    EC:3.2.1.23 (UniProtKB | ENZYME | Rhea)

Activity regulation

Inhibited by high substrate concentrations (100 mg/ml). No effect on activity with various EDTA concentrations (0-1 mM). 20-fold higher activity when cells grown on TOS than when cells grown on galactose, glucose and lactose.

Kinetics

KM SUBSTRATE pH TEMPERATURE[C] NOTES EVIDENCE
60 mMGal(beta1-4)Gal6.037
2.2 mMp-nitrophenyl-beta-D-galactopyranoside (PNPG)6.040
2.2 mMbeta-D-Galp-(1->4)-beta-D-Galp-(1->4)-D-Glcp6.040
4 mMbeta-D-Galp-(1->4)-beta-D-Galp-(1->4)-beta-D-Galp-(1->4)-D-Glcp6.040
3.7 mMbeta-D-Galp-(1->4)-D-Galp6.040
6.4 mMbeta-D-Galp-(1->4)-beta-D-Galp-(1->4)-D-Galp6.040
5.2 mMbeta-D-Galp-(1->4)-beta-D-Galp-(1->4)-beta-D-Galp-(1->4)-D-Galp6.040
Vmax pH TEMPERATURE[C] NOTES EVIDENCE
1.129 μmol/min/mg6.037with Gal(beta1-4)Gal as substrate

pH Dependence

Optimum is pH 6.0 using PNPG or TOS as substrate. Not active below pH 5.

Temperature Dependence

Optimum temperature is 50 degrees Celsius using PNPG as substrate (PubMed:15480628).
Optimum temperature is 35 degrees Celsius using TOS as substrate (PubMed:10742215).
Stable at 40 degrees Celsius. Half-life time at 50 degrees Celsius is 10 minutes.

Features

Showing features for binding site, active site.

TypeIDPosition(s)Description
Binding site122substrate
Binding site160substrate
Active site161Proton donor
Active site320Nucleophile
Binding site328substrate
Binding site368-371substrate

GO annotations

AspectTerm
Cellular Componentbeta-galactosidase complex
Molecular Functionbeta-galactosidase activity
Biological Processcarbohydrate metabolic process

Keywords

Enzyme and pathway databases

Protein family/group databases

Names & Taxonomy

Protein names

  • Recommended name
    Beta-galactosidase BgaB
  • EC number
  • Short names
    Beta-gal
  • Alternative names
    • Beta-Gal II

Gene names

    • Name
      bgaB
    • Synonyms
      bgaLII
    • Ordered locus names
      BAD_1401

Organism names

Accessions

  • Primary accession
    A1A399
  • Secondary accessions
    • Q5J883

Proteomes

Subcellular Location

PTM/Processing

Features

Showing features for initiator methionine, chain.

TypeIDPosition(s)Description
Initiator methionine1Removed
ChainPRO_00004076832-700Beta-galactosidase BgaB

Post-translational modification

The N-terminus is blocked.

Proteomic databases

Interaction

Subunit

Trimer (PubMed:15480628).
Tetramer (PubMed:10742215).

Protein-protein interaction databases

Family & Domains

Sequence similarities

Belongs to the glycosyl hydrolase 42 family.

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    700
  • Mass (Da)
    78,025
  • Last updated
    2011-05-03 v2
  • Checksum
    9EDB064761188A52
MSARRNFEWPELLTADGRGIAFGGDYNPDQWSEDIWDDDIRLMKQAGVNTVALAIFSWDRIQPTEDRWDFGWLDRIIDKLGNAGIVVDLASATATAPLWLYESHPEVLPRDKYGHPVNAGSRQSWSPTSPVFKEYALTLCRKLAERYGTNPYVTAWHMGNEYGWNNREDYSDNALEAFRAWCRRKYGTIDALNQAWGTTFWGQEMNGFDEVLIPRFMGADSMVNPGQKLDFERFGNDMLLDFYKAERDAIAEICPDKPFTTNFMVSTDQCCMDYAAWAKEVNFVSNDHYFHEGESHLDELACSDALMDSLALGKPWYVMEHSTSAVQWKPLNTRKRKGETVRDSLAHVAMGADAINFFQWRASAFGAEAFHSAMVPHAGEDTKLFRQVCELGASLHTLADAGVQGTELAHSDTAILFSAESEWATRSQTLPSMKLNHWHDVRDWYRAFLDAGSRADIVPLAYDWSSYKTVVLPTVLILSAADTQRLADFAAAGGRVVVGYATGLIDEHFHTWLGGYPGAGDGLLRSMLGVRGEEFNILGAEAEGEPGEIRLSSADDSAALDGTTTRLWQNDVNVTGEHAQVLATYAGEEADEWELDGTAAVTRNPYGSGEAYFVGCDLDVADLTKLVRAYLAASSQENADVLHTVRASADATFDFYLPRGKKTVELQGIEGEPVILFQTDREEKPGSYTVRRNGVLVVRR

Sequence caution

The sequence BAF40182.1 differs from that shown. Reason: Erroneous initiation Extended N-terminus.

Features

Showing features for sequence conflict.

TypeIDPosition(s)Description
Sequence conflict213-230in Ref. 1; AAR24113
Sequence conflict536in Ref. 1; AAR24113

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
AY359872
EMBL· GenBank· DDBJ
AAR24113.1
EMBL· GenBank· DDBJ
Genomic DNA
AP009256
EMBL· GenBank· DDBJ
BAF40182.1
EMBL· GenBank· DDBJ
Genomic DNA Different initiation

Genome annotation databases

Similar Proteins

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