A0A7N5K4X9 · A0A7N5K4X9_AILME

Function

function

Hydrolyzes the non-reducing end N-acetyl-D-hexosamine and/or sulfated N-acetyl-D-hexosamine of glycoconjugates, such as the oligosaccharide moieties from proteins and neutral glycolipids, or from certain mucopolysaccharides. The isozyme B does not hydrolyze each of these substrates, however hydrolyzes efficiently neutral oligosaccharide. Only the isozyme A is responsible for the degradation of GM2 gangliosides in the presence of GM2A. During fertilization is responsible, at least in part, for the zona block to polyspermy. Present in the cortical granules of non-activated oocytes, is exocytosed during the cortical reaction in response to oocyte activation and inactivates the sperm galactosyltransferase-binding site, accounting for the block in sperm binding to the zona pellucida.

Catalytic activity

  • N-acetyl-beta-D-6-sulfogalactosaminyl-(1->4)-alpha-L-iduronyl-(1->3)-N-acetyl-D-6-sulfogalactosamine + H2O = alpha-L-iduronyl-(1->3)-N-acetyl-D-6-sulfogalactosamine + N-acetyl-D-6-sulfogalactosamine
    This reaction proceeds in the forward direction.
  • N-acetyl-beta-D-galactosaminyl-(1->4)-beta-D-3-sulfogalactosyl-(1->4)-beta-D-glucosyl-(1<->1')-ceramide + H2O = a beta-D-3-sulfogalactosyl-(1->4)-beta-D-glucosyl-(1<->1')-ceramide + N-acetyl-beta-D-galactosamine
    This reaction proceeds in the forward direction.
  • Hydrolysis of terminal non-reducing N-acetyl-D-hexosamine residues in N-acetyl-beta-D-hexosaminides.
    EC:3.2.1.52 (UniProtKB | ENZYME | Rhea)
  • a ganglioside GM2 (d18:1(4E)) + H2O = a ganglioside GM3 (d18:1(4E)) + N-acetyl-beta-D-galactosamine
    This reaction proceeds in the forward direction.
  • a ganglioside GM2 + H2O = a ganglioside GM3 + N-acetyl-beta-D-galactosamine
    This reaction proceeds in the forward direction.
  • beta-D-GalNAc-(1->4)-alpha-L-IdoA-(1->3)-beta-D-GalNAc-4-sulfate-(1->4)-alpha-L-IdoA-(1->3)-D-GalNAc-4-sulfate + H2O = alpha-L-IdoA-(1->3)-beta-D-GalNAc-4-sulfate-(1->4)-alpha-L-IdoA-(1->3)-D-GalNAc-4-sulfate + N-acetyl-D-galactosamine
    This reaction proceeds in the forward direction.

Features

Showing features for active site.

TypeIDPosition(s)Description
Active site436Proton donor

GO annotations

AspectTerm
Cellular Componentcortical granule
Cellular Componentlysosome
Cellular Componentmembrane
Molecular Functionbeta-N-acetylhexosaminidase activity
Biological Processcarbohydrate metabolic process
Biological Processganglioside catabolic process
Biological Processglycosaminoglycan metabolic process

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    Beta-hexosaminidase subunit beta
  • EC number
  • Alternative names
    • Beta-N-acetylhexosaminidase subunit beta
    • N-acetyl-beta-glucosaminidase subunit beta

Gene names

    • Name
      HEXB

Organism names

  • Taxonomic identifier
  • Taxonomic lineage
    Eukaryota > Metazoa > Chordata > Craniata > Vertebrata > Euteleostomi > Mammalia > Eutheria > Laurasiatheria > Carnivora > Caniformia > Ursidae > Ailuropoda

Accessions

  • Primary accession
    A0A7N5K4X9

Proteomes

Subcellular Location

Keywords

PTM/Processing

Keywords

Interaction

Subunit

There are 3 forms of beta-hexosaminidase: hexosaminidase A is a heterodimer composed of one subunit alpha and one subunit beta (chain A and B); hexosaminidase B is a homodimer of two beta subunits (two chains A and B); hexosaminidase S is a homodimer of two alpha subunits. The composition of the dimer (isozyme A versus isozyme S) has a significant effect on the substrate specificity of the alpha subunit active site.

Family & Domains

Features

Showing features for region, compositional bias, domain.

Type
IDPosition(s)Description
Region1-175Disordered
Compositional bias66-80Pro residues
Compositional bias141-175Basic and acidic residues
Domain181-259Beta-hexosaminidase eukaryotic type N-terminal
Domain281-584Glycoside hydrolase family 20 catalytic

Sequence similarities

Belongs to the glycosyl hydrolase 20 family.

Keywords

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    587
  • Mass (Da)
    65,444
  • Last updated
    2021-06-02 v1
  • MD5 Checksum
    E521E3D4DA597D5FECD2F1755A508506
GRATATPSEAPLSAEEGHWSYPASALRSPAARPGAGGEPDERRSLRRWPASARCGRAAAATEVSAPRAVPPPPPKPEFQPPGRTHASGEHTPAGQAAPASGAGRNRSRAAGKTYGGRDRRQRTTSWVLSPRSPGGRRQGGRLSPGERRRLPGRKERAWGARPGEDSASRPAERLPERDSGRYYDYIFDFNKSRLNPAKHNSAAELKQLLVSVVLESECDLYPSITSDESYTLAVEGPVAFLKANRVWGVLRGLETFSQLIYQDSYGTFTVNESNIIDSPRFPHRGILIDTARHFLPIKTILKTLDAMAFNKFNVLHWHIVDDQSFPYQSVAFPELSNKGSYSLSHVYTPNDVRTVIEYARLRGIRVIPEFDSPGHTQSWGKGQKNLLTPCYNGPKQSGTFGPINPILNSTYCFLSQFFKEVSTMFPDQFVHLGGDEVEFTCWESNPEVIAFMKKAGFGRDFQRLQSFYIQKLLGIVSTLNKGAIVWQEVFDDHAKLNPGTVVQVWKNEMYHVTQAAVTAAGFPVILSAPWYLDWISYGQDWRNYYKVDPLDFDGSQEQKKLVIGGEACLWGEYVDATNLTPRLWYGI

Computationally mapped potential isoform sequences

There is 1 potential isoform mapped to this entry

View all
EntryEntry nameGene nameLength
G1L108G1L108_AILMEHEXB524

Features

Showing features for compositional bias.

TypeIDPosition(s)Description
Compositional bias66-80Pro residues
Compositional bias141-175Basic and acidic residues

Keywords

Genome annotation databases

Similar Proteins

Disclaimer

Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care. Our staff consists of biologists and biochemists that are not trained to give medical advice.
We'd like to inform you that we have updated our Privacy Notice to comply with Europe’s new General Data Protection Regulation (GDPR) that applies since 25 May 2018.
Help