ID   HEXB_RAT                Reviewed;         537 AA.
AC   Q6AXR4;
DT   10-MAY-2005, integrated into UniProtKB/Swiss-Prot.
DT   13-SEP-2004, sequence version 1.
DT   02-SEP-2026, entry version 130.
DE   RecName: Full=Beta-hexosaminidase subunit beta {ECO:0000305};
DE            EC=3.2.1.52 {ECO:0000250|UniProtKB:P07686};
DE   AltName: Full=Beta-N-acetylhexosaminidase subunit beta;
DE            Short=Hexosaminidase subunit B;
DE   AltName: Full=N-acetyl-beta-glucosaminidase subunit beta;
DE   Flags: Precursor;
GN   Name=Hexb {ECO:0000312|RGD:1307607};
OS   Rattus norvegicus (Rat).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC   Eutheria; Euarchontoglires; Glires; Rodentia; Myomorpha; Muroidea; Muridae;
OC   Murinae; Rattus.
OX   NCBI_TaxID=10116;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
RC   TISSUE=Kidney;
RX   PubMed=15489334; DOI=10.1101/gr.2596504;
RG   The MGC Project Team;
RT   "The status, quality, and expansion of the NIH full-length cDNA project:
RT   the Mammalian Gene Collection (MGC).";
RL   Genome Res. 14:2121-2127(2004).
CC   -!- FUNCTION: Hydrolyzes the non-reducing end N-acetyl-D-hexosamine and/or
CC       sulfated N-acetyl-D-hexosamine of glycoconjugates, such as the
CC       oligosaccharide moieties from proteins and neutral glycolipids, or from
CC       certain mucopolysaccharides. The isozyme B does not hydrolyze each of
CC       these substrates, however hydrolyzes efficiently neutral
CC       oligosaccharide. Only the isozyme A is responsible for the degradation
CC       of GM2 gangliosides in the presence of GM2A (By similarity). During
CC       fertilization is responsible, at least in part, for the zona block to
CC       polyspermy. Present in the cortical granules of non-activated oocytes,
CC       is exocytosed during the cortical reaction in response to oocyte
CC       activation and inactivates the sperm galactosyltransferase-binding
CC       site, accounting for the block in sperm binding to the zona pellucida
CC       (By similarity). {ECO:0000250|UniProtKB:P07686,
CC       ECO:0000250|UniProtKB:P20060}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=Hydrolysis of terminal non-reducing N-acetyl-D-hexosamine
CC         residues in N-acetyl-beta-D-hexosaminides.; EC=3.2.1.52;
CC         Evidence={ECO:0000250|UniProtKB:P07686};
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=N-acetyl-beta-D-galactosaminyl-(1->4)-beta-D-3-
CC         sulfogalactosyl-(1->4)-beta-D-glucosyl-(1<->1')-ceramide + H2O = a
CC         beta-D-3-sulfogalactosyl-(1->4)-beta-D-glucosyl-(1<->1')-ceramide +
CC         N-acetyl-beta-D-galactosamine; Xref=Rhea:RHEA:48276,
CC         ChEBI:CHEBI:15377, ChEBI:CHEBI:28497, ChEBI:CHEBI:90163,
CC         ChEBI:CHEBI:90164; Evidence={ECO:0000250|UniProtKB:P07686};
CC       PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:48277;
CC         Evidence={ECO:0000250|UniProtKB:P07686};
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=a ganglioside GM2 (d18:1(4E)) + H2O = a ganglioside GM3
CC         (d18:1(4E)) + N-acetyl-beta-D-galactosamine; Xref=Rhea:RHEA:47940,
CC         ChEBI:CHEBI:15377, ChEBI:CHEBI:28497, ChEBI:CHEBI:60065,
CC         ChEBI:CHEBI:71502; Evidence={ECO:0000250|UniProtKB:P07686};
CC       PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:47941;
CC         Evidence={ECO:0000250|UniProtKB:P07686};
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=a ganglioside GM2 + H2O = a ganglioside GM3 + N-acetyl-beta-D-
CC         galactosamine; Xref=Rhea:RHEA:47968, ChEBI:CHEBI:15377,
CC         ChEBI:CHEBI:28497, ChEBI:CHEBI:79210, ChEBI:CHEBI:79218;
CC         Evidence={ECO:0000250|UniProtKB:P07686};
CC       PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:47969;
CC         Evidence={ECO:0000250|UniProtKB:P07686};
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=beta-D-GalNAc-(1->4)-alpha-L-IdoA-(1->3)-beta-D-GalNAc-4-
CC         sulfate-(1->4)-alpha-L-IdoA-(1->3)-D-GalNAc-4-sulfate + H2O = alpha-
CC         L-IdoA-(1->3)-beta-D-GalNAc-4-sulfate-(1->4)-alpha-L-IdoA-(1->3)-D-
CC         GalNAc-4-sulfate + N-acetyl-D-galactosamine; Xref=Rhea:RHEA:64372,
CC         ChEBI:CHEBI:15377, ChEBI:CHEBI:28037, ChEBI:CHEBI:152565,
CC         ChEBI:CHEBI:152566; Evidence={ECO:0000250|UniProtKB:P07686};
CC       PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:64373;
CC         Evidence={ECO:0000250|UniProtKB:P07686};
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=N-acetyl-beta-D-6-sulfogalactosaminyl-(1->4)-alpha-L-iduronyl-
CC         (1->3)-N-acetyl-D-6-sulfogalactosamine + H2O = alpha-L-iduronyl-
CC         (1->3)-N-acetyl-D-6-sulfogalactosamine + N-acetyl-D-6-
CC         sulfogalactosamine; Xref=Rhea:RHEA:64384, ChEBI:CHEBI:15377,
CC         ChEBI:CHEBI:152567, ChEBI:CHEBI:152568, ChEBI:CHEBI:153064;
CC         Evidence={ECO:0000250|UniProtKB:P07686};
CC       PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:64385;
CC         Evidence={ECO:0000250|UniProtKB:P07686};
CC   -!- ACTIVITY REGULATION: Addition of GM2A stimulates the hydrolysis of
CC       sulfated glycosphingolipid SM2 and the ganglioside GM2.
CC       {ECO:0000250|UniProtKB:P07686}.
CC   -!- SUBUNIT: There are 3 forms of beta-hexosaminidase: hexosaminidase A is
CC       a heterodimer composed of one subunit alpha and one subunit beta (chain
CC       A and B); hexosaminidase B is a homodimer of two beta subunits (two
CC       chains A and B); hexosaminidase S is a homodimer of two alpha subunits
CC       (By similarity). The composition of the dimer (isozyme A versus isozyme
CC       S) has a significant effect on the substrate specificity of the alpha
CC       subunit active site (By similarity). {ECO:0000250|UniProtKB:P06865,
CC       ECO:0000250|UniProtKB:P07686}.
CC   -!- SUBCELLULAR LOCATION: Lysosome {ECO:0000250|UniProtKB:P07686}.
CC       Cytoplasmic vesicle, secretory vesicle, Cortical granule
CC       {ECO:0000250|UniProtKB:P20060}.
CC   -!- SIMILARITY: Belongs to the glycosyl hydrolase 20 family. {ECO:0000305}.
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DR   EMBL; BC079376; AAH79376.1; -; mRNA.
DR   RefSeq; NP_001011946.1; NM_001011946.2.
DR   AlphaFoldDB; Q6AXR4; -.
DR   SMR; Q6AXR4; -.
DR   FunCoup; Q6AXR4; 1536.
DR   STRING; 10116.ENSRNOP00000044480; -.
DR   GlyCosmos; Q6AXR4; 3 sites, No reported glycans.
DR   GlyGen; Q6AXR4; 4 sites, 1 O-linked glycan (1 site).
DR   iPTMnet; Q6AXR4; -.
DR   PhosphoSitePlus; Q6AXR4; -.
DR   jPOST; Q6AXR4; -.
DR   PaxDb; 10116-ENSRNOP00000044480; -.
DR   PeptideAtlas; Q6AXR4; -.
DR   Ensembl; ENSRNOT00000097138.2; ENSRNOP00000081104.1; ENSRNOG00000025274.8.
DR   Ensembl; ENSRNOT00055049454; ENSRNOP00055040704; ENSRNOG00055028545.
DR   Ensembl; ENSRNOT00060049231; ENSRNOP00060041090; ENSRNOG00060028290.
DR   Ensembl; ENSRNOT00065037610; ENSRNOP00065030400; ENSRNOG00065022045.
DR   GeneID; 294673; -.
DR   KEGG; rno:294673; -.
DR   UCSC; RGD:1307607; rat.
DR   AGR; RGD:1307607; -.
DR   CTD; 3074; -.
DR   RGD; 1307607; Hexb.
DR   eggNOG; KOG2499; Eukaryota.
DR   GeneTree; ENSGT00390000008107; -.
DR   InParanoid; Q6AXR4; -.
DR   OrthoDB; 428480at2759; -.
DR   PhylomeDB; Q6AXR4; -.
DR   Reactome; R-RNO-2022857; Keratan sulfate degradation.
DR   Reactome; R-RNO-2024101; CS/DS degradation.
DR   Reactome; R-RNO-2160916; Hyaluronan degradation.
DR   Reactome; R-RNO-6798695; Neutrophil degranulation.
DR   Reactome; R-RNO-9840310; Glycosphingolipid catabolism.
DR   SABIO-RK; Q6AXR4; -.
DR   PRO; PR:Q6AXR4; -.
DR   Proteomes; UP000002494; Chromosome 2.
DR   ExpressionAtlas; Q6AXR4; baseline and differential.
DR   GO; GO:0001669; C:acrosomal vesicle; ISO:RGD.
DR   GO; GO:0042582; C:azurophil granule; ISO:RGD.
DR   GO; GO:1905379; C:beta-N-acetylhexosaminidase complex; IEA:Ensembl.
DR   GO; GO:0060473; C:cortical granule; ISS:UniProtKB.
DR   GO; GO:0005576; C:extracellular region; ISO:RGD.
DR   GO; GO:0005764; C:lysosome; ISS:UniProtKB.
DR   GO; GO:0016020; C:membrane; ISO:RGD.
DR   GO; GO:0008375; F:acetylglucosaminyltransferase activity; ISO:RGD.
DR   GO; GO:0016231; F:beta-N-acetylglucosaminidase activity; IDA:RGD.
DR   GO; GO:0004563; F:beta-N-acetylhexosaminidase activity; ISS:UniProtKB.
DR   GO; GO:0030246; F:carbohydrate binding; IDA:RGD.
DR   GO; GO:0015929; F:hexosaminidase activity; IDA:RGD.
DR   GO; GO:0016787; F:hydrolase activity; ISO:RGD.
DR   GO; GO:0042802; F:identical protein binding; IPI:RGD.
DR   GO; GO:0044877; F:protein-containing complex binding; IDA:RGD.
DR   GO; GO:0043615; P:astrocyte cell migration; ISO:RGD.
DR   GO; GO:0030207; P:chondroitin sulfate proteoglycan catabolic process; ISO:RGD.
DR   GO; GO:0030209; P:dermatan sulfate proteoglycan catabolic process; ISO:RGD.
DR   GO; GO:0006689; P:ganglioside catabolic process; ISS:UniProtKB.
DR   GO; GO:0030203; P:glycosaminoglycan metabolic process; ISO:RGD.
DR   GO; GO:0006687; P:glycosphingolipid metabolic process; ISO:RGD.
DR   GO; GO:0030214; P:hyaluronan catabolic process; ISO:RGD.
DR   GO; GO:0006874; P:intracellular calcium ion homeostasis; ISO:RGD.
DR   GO; GO:0019915; P:lipid storage; ISO:RGD.
DR   GO; GO:0007626; P:locomotory behavior; ISO:RGD.
DR   GO; GO:0007040; P:lysosome organization; ISO:RGD.
DR   GO; GO:0008049; P:male courtship behavior; ISO:RGD.
DR   GO; GO:0042552; P:myelination; ISO:RGD.
DR   GO; GO:0006044; P:N-acetylglucosamine metabolic process; IDA:RGD.
DR   GO; GO:0050905; P:neuromuscular process; ISO:RGD.
DR   GO; GO:0050885; P:neuromuscular process controlling balance; ISO:RGD.
DR   GO; GO:0009313; P:oligosaccharide catabolic process; ISO:RGD.
DR   GO; GO:0048477; P:oogenesis; ISO:RGD.
DR   GO; GO:0007341; P:penetration of zona pellucida; ISO:RGD.
DR   GO; GO:0008654; P:phospholipid biosynthetic process; ISO:RGD.
DR   GO; GO:0045944; P:positive regulation of transcription by RNA polymerase II; ISO:RGD.
DR   GO; GO:0008360; P:regulation of cell shape; ISO:RGD.
DR   GO; GO:0007605; P:sensory perception of sound; ISO:RGD.
DR   GO; GO:0007338; P:single fertilization; ISS:UniProtKB.
DR   GO; GO:0001501; P:skeletal system development; ISO:RGD.
DR   CDD; cd06562; GH20_HexA_HexB-like; 1.
DR   FunFam; 3.20.20.80:FF:000049; Beta-hexosaminidase A; 1.
DR   FunFam; 3.30.379.10:FF:000001; Beta-hexosaminidase subunit beta; 1.
DR   Gene3D; 3.30.379.10; Chitobiase/beta-hexosaminidase domain 2-like; 1.
DR   Gene3D; 3.20.20.80; Glycosidases; 1.
DR   InterPro; IPR025705; GH20.
DR   InterPro; IPR015883; GH20_cat.
DR   InterPro; IPR017853; GH_hydrolase_sf.
DR   InterPro; IPR029018; Hex-like_dom2.
DR   InterPro; IPR029019; HEX_eukaryotic_N.
DR   PANTHER; PTHR22600; BETA-HEXOSAMINIDASE; 1.
DR   PANTHER; PTHR22600:SF38; BETA-HEXOSAMINIDASE SUBUNIT BETA; 1.
DR   Pfam; PF00728; Glyco_hydro_20; 1.
DR   Pfam; PF14845; Glycohydro_20b2; 1.
DR   PIRSF; PIRSF001093; B-hxosamndse_ab_euk; 1.
DR   PRINTS; PR00738; GLHYDRLASE20.
DR   SUPFAM; SSF51445; (Trans)glycosidases; 1.
DR   SUPFAM; SSF55545; beta-N-acetylhexosaminidase-like domain; 1.
PE   2: Evidence at transcript level;
KW   Cytoplasmic vesicle; Disulfide bond; Glycoprotein; Glycosidase; Hydrolase;
KW   Lipid metabolism; Lysosome; Reference proteome; Signal.
FT   SIGNAL          1..23
FT                   /evidence="ECO:0000255"
FT   CHAIN           24..537
FT                   /note="Beta-hexosaminidase subunit beta"
FT                   /id="PRO_0000012008"
FT   ACT_SITE        333
FT                   /note="Proton donor"
FT                   /evidence="ECO:0000250"
FT   CARBOHYD        62
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        168
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        305
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   DISULFID        69..115
FT                   /evidence="ECO:0000250"
FT   DISULFID        287..338
FT                   /evidence="ECO:0000250"
FT   DISULFID        512..529
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   537 AA;  61527 MW;  1A9BB01F4AD2F6E4 CRC64;
     MPGSPRRAPG LLLQALVAMV SLALVAPFGL QPALWPMPRS VQVFPRLLYI SPENFQIDNS
     PNSTAGPSCS LLLEAFRRYY NYIFGFYKRH HGPAKFQDKP QLEKLLVFIN LEPQCDAFPS
     MSSDESYSLL VQEPVALLKA NEVWGALRGL ETFSQLVYQD AYGTFTINES TIADSPRFPH
     RGILIDTSRH YLPVKTIFKT LDAMAFNKFN VLHWHIVDDQ SFPYQSITFP ELSNKGSYSL
     SHVYTPNDIH MVLEYARLRG IRVIPEFDSP GHTQSWGKGQ KNLLTPCFIQ KIRTQKVGPV
     DPSLNTTYVF FDTFFKEISR VFPDQFIHLG GDEVEFECWA SNPNIQNFMK KKGFGNNFRR
     LESFYIKKIL DIITSLKKSS IVWQDVFDDQ VELQPGTVVE VWKSENYLNE LAQVTASGFP
     AILSAPWYLD LISYGQDWRN YYKAEPLNFE GSEKQKQLVI GGEACLWGEY VDATNLIPRL
     WPRASAVGER LWSPRIITNL ENAYRRLAVH RCRMVSRGIA AQPLFTGYCN YENKMEK
//