Gene/Proteome Database (LMPD)

LMPD ID
LMP000083
Gene ID
3074
Species
Homo sapiens (Human)
Gene Name
hexosaminidase B (beta polypeptide)
Gene Symbol
HEXB
Synonyms
ENC-1AS; HEL-248
Chromosome
5
Map Location
5q13
EC Number
3.2.1.52
Summary
Hexosaminidase B is the beta subunit of the lysosomal enzyme beta-hexosaminidase that, together with the cofactor GM2 activator protein, catalyzes the degradation of the ganglioside GM2, and other molecules containing terminal N-acetyl hexosamines. Beta-hexosaminidase is composed of two subunits, alpha and beta, which are encoded by separate genes. Both beta-hexosaminidase alpha and beta subunits are members of family 20 of glycosyl hydrolases. Mutations in the alpha or beta subunit genes lead to an accumulation of GM2 ganglioside in neurons and neurodegenerative disorders termed the GM2 gangliosidoses. Beta subunit gene mutations lead to Sandhoff disease (GM2-gangliosidosis type II). Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, May 2014]
Orthologs
View orthologs and multiple alignments for HEXB

Proteins

beta-hexosaminidase subunit beta isoform 1 preproprotein
Refseq ID NP_000512
Protein GI 4504373
UniProt ID P07686
mRNA ID NM_000521
Length 556
RefSeq Status REVIEWED
MELCGLGLPRPPMLLALLLATLLAAMLALLTQVALVVQVAEAARAPSVSAKPGPALWPLPLSVKMTPNLLHLAPENFYISHSPNSTAGPSCTLLEEAFRRYHGYIFGFYKWHHEPAEFQAKTQVQQLLVSITLQSECDAFPNISSDESYTLLVKEPVAVLKANRVWGALRGLETFSQLVYQDSYGTFTINESTIIDSPRFSHRGILIDTSRHYLPVKIILKTLDAMAFNKFNVLHWHIVDDQSFPYQSITFPELSNKGSYSLSHVYTPNDVRMVIEYARLRGIRVLPEFDTPGHTLSWGKGQKDLLTPCYSRQNKLDSFGPINPTLNTTYSFLTTFFKEISEVFPDQFIHLGGDEVEFKCWESNPKIQDFMRQKGFGTDFKKLESFYIQKVLDIIATINKGSIVWQEVFDDKAKLAPGTIVEVWKDSAYPEELSRVTASGFPVILSAPWYLDLISYGQDWRKYYKVEPLDFGGTQKQKQLFIGGEACLWGEYVDATNLTPRLWPRASAVGERLWSSKDVRDMDDAYDRLTRHRCRMVERGIAAQPLYAGYCNHENM
beta-hexosaminidase subunit beta isoform 2
Refseq ID NP_001278933
Protein GI 635172849
UniProt ID P07686
mRNA ID NM_001292004
Length 331
RefSeq Status REVIEWED
MAFNKFNVLHWHIVDDQSFPYQSITFPELSNKGSYSLSHVYTPNDVRMVIEYARLRGIRVLPEFDTPGHTLSWGKGQKDLLTPCYSRQNKLDSFGPINPTLNTTYSFLTTFFKEISEVFPDQFIHLGGDEVEFKCWESNPKIQDFMRQKGFGTDFKKLESFYIQKVLDIIATINKGSIVWQEVFDDKAKLAPGTIVEVWKDSAYPEELSRVTASGFPVILSAPWYLDLISYGQDWRKYYKVEPLDFGGTQKQKQLFIGGEACLWGEYVDATNLTPRLWPRASAVGERLWSSKDVRDMDDAYDRLTRHRCRMVERGIAAQPLYAGYCNHENM
sig_peptide: 1..42 inference: non-experimental evidence, no additional details recorded note: Potential; propagated from UniProtKB/Swiss-Prot (P07686.3) calculated_mol_wt: 4343 peptide sequence: MELCGLGLPRPPMLLALLLATLLAAMLALLTQVALVVQVAEA mat_peptide: 122..556 product: Beta-hexosaminidase subunit beta experiment: experimental evidence, no additional details recorded note: propagated from UniProtKB/Swiss-Prot (P07686.3) calculated_mol_wt: 49927 peptide sequence: TQVQQLLVSITLQSECDAFPNISSDESYTLLVKEPVAVLKANRVWGALRGLETFSQLVYQDSYGTFTINESTIIDSPRFSHRGILIDTSRHYLPVKIILKTLDAMAFNKFNVLHWHIVDDQSFPYQSITFPELSNKGSYSLSHVYTPNDVRMVIEYARLRGIRVLPEFDTPGHTLSWGKGQKDLLTPCYSRQNKLDSFGPINPTLNTTYSFLTTFFKEISEVFPDQFIHLGGDEVEFKCWESNPKIQDFMRQKGFGTDFKKLESFYIQKVLDIIATINKGSIVWQEVFDDKAKLAPGTIVEVWKDSAYPEELSRVTASGFPVILSAPWYLDLISYGQDWRKYYKVEPLDFGGTQKQKQLFIGGEACLWGEYVDATNLTPRLWPRASAVGERLWSSKDVRDMDDAYDRLTRHRCRMVERGIAAQPLYAGYCNHENM mat_peptide: 122..311 product: Beta-hexosaminidase subunit beta chain B experiment: experimental evidence, no additional details recorded note: propagated from UniProtKB/Swiss-Prot (P07686.3) calculated_mol_wt: 21631 peptide sequence: TQVQQLLVSITLQSECDAFPNISSDESYTLLVKEPVAVLKANRVWGALRGLETFSQLVYQDSYGTFTINESTIIDSPRFSHRGILIDTSRHYLPVKIILKTLDAMAFNKFNVLHWHIVDDQSFPYQSITFPELSNKGSYSLSHVYTPNDVRMVIEYARLRGIRVLPEFDTPGHTLSWGKGQKDLLTPCYS mat_peptide: 315..556 product: Beta-hexosaminidase subunit beta chain A experiment: experimental evidence, no additional details recorded note: propagated from UniProtKB/Swiss-Prot (P07686.3) calculated_mol_wt: 27916 peptide sequence: KLDSFGPINPTLNTTYSFLTTFFKEISEVFPDQFIHLGGDEVEFKCWESNPKIQDFMRQKGFGTDFKKLESFYIQKVLDIIATINKGSIVWQEVFDDKAKLAPGTIVEVWKDSAYPEELSRVTASGFPVILSAPWYLDLISYGQDWRKYYKVEPLDFGGTQKQKQLFIGGEACLWGEYVDATNLTPRLWPRASAVGERLWSSKDVRDMDDAYDRLTRHRCRMVERGIAAQPLYAGYCNHENM

Gene Information

Entrez Gene ID
3074
Gene Name
hexosaminidase B (beta polypeptide)
Gene Symbol
HEXB
Species
Homo sapiens

Gene Ontology (GO Annotations)

GO ID Source Type Description
GO:0001669 IEA:Ensembl C acrosomal vesicle
GO:0070062 IDA:UniProtKB C extracellular vesicular exosome
GO:0043202 TAS:Reactome C lysosomal lumen
GO:0016020 IDA:UniProtKB C membrane
GO:0004563 TAS:ProtInc F beta-N-acetylhexosaminidase activity
GO:0046982 IDA:MGI F protein heterodimerization activity
GO:0042803 IDA:MGI F protein homodimerization activity
GO:0043615 IEA:Ensembl P astrocyte cell migration
GO:0005975 TAS:Reactome P carbohydrate metabolic process
GO:0008219 IEA:UniProtKB-KW P cell death
GO:0006874 IEA:Ensembl P cellular calcium ion homeostasis
GO:0044267 IEA:Ensembl P cellular protein metabolic process
GO:0030207 TAS:Reactome P chondroitin sulfate catabolic process
GO:0030204 TAS:Reactome P chondroitin sulfate metabolic process
GO:0006689 IEA:Ensembl P ganglioside catabolic process
GO:0030203 TAS:Reactome P glycosaminoglycan metabolic process
GO:0006687 TAS:Reactome P glycosphingolipid metabolic process
GO:0030214 TAS:Reactome P hyaluronan catabolic process
GO:0030212 TAS:Reactome P hyaluronan metabolic process
GO:0042340 TAS:Reactome P keratan sulfate catabolic process
GO:0042339 TAS:Reactome P keratan sulfate metabolic process
GO:0019915 IEA:Ensembl P lipid storage
GO:0007626 IEA:Ensembl P locomotory behavior
GO:0007040 IEA:Ensembl P lysosome organization
GO:0008049 IEA:Ensembl P male courtship behavior
GO:0042552 IEA:Ensembl P myelination
GO:0050885 IEA:Ensembl P neuromuscular process controlling balance
GO:0009313 IEA:Ensembl P oligosaccharide catabolic process
GO:0048477 IEA:Ensembl P oogenesis
GO:0007341 IEA:Ensembl P penetration of zona pellucida
GO:0008654 IEA:Ensembl P phospholipid biosynthetic process
GO:0045944 IEA:Ensembl P positive regulation of transcription from RNA polymerase II promoter
GO:0008360 IEA:Ensembl P regulation of cell shape
GO:0007605 IEA:Ensembl P sensory perception of sound
GO:0001501 IEA:Ensembl P skeletal system development
GO:0044281 TAS:Reactome P small molecule metabolic process
GO:0006665 TAS:Reactome P sphingolipid metabolic process

KEGG Pathway Links

KEGG Pathway ID Description
hsa04142 Lysosome

REACTOME Pathway Links

REACTOME Pathway ID Description
REACT_120888 CS/DS degradation
REACT_120996 Hyaluronan uptake and degradation
REACT_121313 Keratan sulfate degradation

Domain Information

InterPro Annotations

Accession Description
IPR029019 Beta-hexosaminidase, eukaryotic type, N-terminal
IPR025705 Beta_hexosaminidase_sua/sub
IPR029018 Chitobiase/beta-hexosaminidase domain 2-like
IPR015883 Glycoside hydrolase family 20, catalytic core
IPR017853 Glycoside hydrolase superfamily
IPR013781 Glycoside hydrolase, catalytic domain

UniProt Annotations

Entry Information

Gene Name
hexosaminidase B (beta polypeptide)
Protein Entry
P07686_HUMAN
UniProt ID
P07686
Species
Human

Comments

Comment Type Description
Catalytic Activity Hydrolysis of terminal non-reducing N-acetyl- D-hexosamine residues in N-acetyl-beta-D-hexosaminides.
Disease GM2-gangliosidosis 2 (GM2G2) [MIM
Function Responsible for the degradation of GM2 gangliosides, and a variety of other molecules containing terminal N-acetyl hexosamines, in the brain and other tissues.
Ptm N-linked glycans at Asn-142 and Asn-190 consist of Man(3)- GlcNAc(2) and Man(5 to 7)-GlcNAc(2), respectively. {ECO
Ptm The beta-A and beta-B chains are produced by proteolytic processing of the precursor beta chain.
Sequence Caution Sequence=AAA51828.1; Type=Frameshift; Positions=21; Evidence= ; Sequence=AAA68620.1; Type=Erroneous initiation; Evidence= ;
Similarity Belongs to the glycosyl hydrolase 20 family.
Subcellular Location Lysosome.
Subunit There are 3 forms of beta-hexosaminidase: hexosaminidase A is a trimer composed of one subunit alpha, one subunit beta chain A and one subunit beta chain B; hexosaminidase B is a tetramer of two subunit beta chains A and two subunit beta chains B; hexosaminidase S is a homodimer of two alpha subunits. The two beta chains are derived from the cleavage of the beta subunit.
Web Resource Name=HEXBdb; Note=HEXB mutation database; URL="http://www.hexdb.mcgill.ca/?Topic=HEXBdb";

Identical and Related Proteins

Unique RefSeq proteins for LMP000083 (as displayed in Record Overview)

Protein GI Database Accession Length Protein Name
4504373 RefSeq NP_000512 556 beta-hexosaminidase subunit beta isoform 1 preproprotein
635172849 RefSeq NP_001278933 331 beta-hexosaminidase subunit beta isoform 2

Identical Sequences to LMP000083 proteins

Reference Database Accession Length Protein Name
GI:635172849 GenBank AAV48875.1 331 ENC-1AS [Homo sapiens]
GI:4504373 GenBank EAW95741.1 556 hexosaminidase B (beta polypeptide), isoform CRA_a [Homo sapiens]
GI:4504373 GenBank EAW95742.1 556 hexosaminidase B (beta polypeptide), isoform CRA_a [Homo sapiens]
GI:635172849 GenBank ACI46028.1 331 epididymis luminal protein 248 [Homo sapiens]
GI:4504373 GenBank ADZ15570.1 556 hexosaminidase B (beta polypeptide), partial [synthetic construct]
GI:4504373 GenBank AIC54537.1 556 HEXB, partial [synthetic construct]
GI:4504373 PDB 3LMY 556 Chain A, The Crystal Structure Of Beta-Hexosaminidase B In Complex With Pyrimethamine
GI:4504373 PDB 3LMY 556 Chain B, The Crystal Structure Of Beta-Hexosaminidase B In Complex With Pyrimethamine

Related Sequences to LMP000083 proteins

Reference Database Accession Length Protein Name
GI:635172849 GenBank AAA52645.1 556 beta-hexosaminidase beta-subunit, partial [Homo sapiens]
GI:4504373 GenBank AAP36579.1 557 Homo sapiens hexosaminidase B (beta polypeptide), partial [synthetic construct]
GI:4504373 GenBank AAX29585.1 557 hexosaminidase B, partial [synthetic construct]
GI:635172849 GenBank AAX42123.1 556 hexosaminidase B [synthetic construct]
GI:635172849 GenBank EAW95741.1 556 hexosaminidase B (beta polypeptide), isoform CRA_a [Homo sapiens]
GI:635172849 GenBank EAW95742.1 556 hexosaminidase B (beta polypeptide), isoform CRA_a [Homo sapiens]
GI:635172849 GenBank ADZ15570.1 556 hexosaminidase B (beta polypeptide), partial [synthetic construct]
GI:4504373 GenBank JAA05181.1 556 hexosaminidase B (beta polypeptide) [Pan troglodytes]
GI:4504373 GenBank JAA21905.1 556 hexosaminidase B (beta polypeptide) [Pan troglodytes]
GI:4504373 GenBank JAA31399.1 556 hexosaminidase B (beta polypeptide) [Pan troglodytes]
GI:4504373 RefSeq XP_009447292.1 556 PREDICTED: beta-hexosaminidase subunit beta [Pan troglodytes]
GI:635172849 SwissProt P07686.3 556 RecName: Full=Beta-hexosaminidase subunit beta; AltName: Full=Beta-N-acetylhexosaminidase subunit beta; Short=Hexosaminidase subunit B; AltName: Full=Cervical cancer proto-oncogene 7 protein; Short=HCC-7; AltName: Full=N-acetyl-beta-glucosaminidase subunit beta; Contains: RecName: Full=Beta-hexosaminidase subunit beta chain B; Contains: RecName: Full=Beta-hexosaminidase subunit beta chain A; Flags: Precursor [Homo sapiens]