HEXB_PIG
ID HEXB_PIG Reviewed; 531 AA.
AC Q29548;
DT 30-MAY-2000, integrated into UniProtKB/Swiss-Prot.
DT 10-MAY-2005, sequence version 2.
DT 25-MAY-2022, entry version 122.
DE RecName: Full=Beta-hexosaminidase subunit beta {ECO:0000250|UniProtKB:P07686};
DE EC=3.2.1.52 {ECO:0000250|UniProtKB:P07686};
DE AltName: Full=65 kDa epididymal boar protein;
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:0000250|UniProtKB:P07686};
OS Sus scrofa (Pig).
OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC Eutheria; Laurasiatheria; Artiodactyla; Suina; Suidae; Sus.
OX NCBI_TaxID=9823;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA].
RC TISSUE=Epididymis;
RA Syntin P., Okamura N., Guillou F., Dacheux F., Dacheux J.-L.;
RT "Purification, cloning and sequencing analysis of B-N-acetyl-hexosaminidase
RT from epididymal boar.";
RL Submitted (OCT-1995) to the EMBL/GenBank/DDBJ databases.
RN [2]
RP PARTIAL PROTEIN SEQUENCE.
RC TISSUE=Epididymis;
RX PubMed=8902205; DOI=10.1095/biolreprod55.5.956;
RA Syntin P., Dacheux F., Druart X., Gatti J.L., Okamura N., Dacheux J.-L.;
RT "Characterization and identification of proteins secreted in the various
RT regions of the adult boar epididymis.";
RL Biol. Reprod. 55:956-974(1996).
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=H2O + N-acetyl-beta-D-galactosaminyl-(1->4)-beta-D-3-
CC sulfogalactosyl-(1->4)-beta-D-glucosyl-(1<->1')-ceramide = a beta-D-
CC 3-sulfogalactosyl-(1->4)-beta-D-glucosyl-(1<->1')-ceramide + N-
CC acetyl-beta-D-galactosamine; Xref=Rhea:RHEA:48276, ChEBI:CHEBI:15377,
CC ChEBI:CHEBI:28497, ChEBI:CHEBI:90163, ChEBI:CHEBI:90164;
CC 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=ganglioside GM2 (d18:1(4E)) + H2O = 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=ganglioside GM2 + H2O = 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=H2O + N-acetyl-beta-D-6-sulfogalactosaminyl-(1->4)-alpha-L-
CC iduronyl-(1->3)-N-acetyl-D-6-sulfogalactosamine = 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 an heterodimer composed of one subunit alpha and one subunit beta
CC (chain A and B); hexosaminidase B is an homodimer of two beta subunits
CC (two chains A and B); hexosaminidase S is a homodimer of two alpha
CC subunits (By similarity). The composition of the dimer (isozyme A
CC versus isozyme S) has a significant effect on the substrate specificity
CC of the alpha subunit active site (By similarity).
CC {ECO:0000250|UniProtKB:P06865, 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}.
CC -!- SEQUENCE CAUTION:
CC Sequence=CAA63123.1; Type=Frameshift; Evidence={ECO:0000305};
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DR EMBL; X92379; CAA63123.1; ALT_FRAME; mRNA.
DR RefSeq; NP_999086.1; NM_213921.1.
DR AlphaFoldDB; Q29548; -.
DR SMR; Q29548; -.
DR STRING; 9823.ENSSSCP00000014965; -.
DR CAZy; GH20; Glycoside Hydrolase Family 20.
DR PaxDb; Q29548; -.
DR PeptideAtlas; Q29548; -.
DR PRIDE; Q29548; -.
DR GeneID; 396958; -.
DR KEGG; ssc:396958; -.
DR CTD; 3074; -.
DR eggNOG; KOG2499; Eukaryota.
DR InParanoid; Q29548; -.
DR OrthoDB; 545162at2759; -.
DR Proteomes; UP000008227; Unplaced.
DR Proteomes; UP000314985; Unplaced.
DR GO; GO:0060473; C:cortical granule; ISS:UniProtKB.
DR GO; GO:0005764; C:lysosome; IBA:GO_Central.
DR GO; GO:0016020; C:membrane; IBA:GO_Central.
DR GO; GO:0004563; F:beta-N-acetylhexosaminidase activity; ISS:UniProtKB.
DR GO; GO:0102148; F:N-acetyl-beta-D-galactosaminidase activity; IEA:UniProtKB-EC.
DR GO; GO:0005975; P:carbohydrate metabolic process; IEA:InterPro.
DR GO; GO:0006689; P:ganglioside catabolic process; ISS:UniProtKB.
DR GO; GO:0030203; P:glycosaminoglycan metabolic process; IBA:GO_Central.
DR GO; GO:0007338; P:single fertilization; ISS:UniProtKB.
DR Gene3D; 3.30.379.10; -; 1.
DR InterPro; IPR025705; Beta_hexosaminidase_sua/sub.
DR InterPro; IPR015883; Glyco_hydro_20_cat.
DR InterPro; IPR017853; Glycoside_hydrolase_SF.
DR InterPro; IPR029018; Hex-like_dom2.
DR InterPro; IPR029019; HEX_eukaryotic_N.
DR PANTHER; PTHR22600; PTHR22600; 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; SSF51445; 1.
DR SUPFAM; SSF55545; SSF55545; 1.
PE 1: Evidence at protein level;
KW Cytoplasmic vesicle; Direct protein sequencing; Disulfide bond;
KW Glycoprotein; Glycosidase; Hydrolase; Lipid metabolism; Lysosome;
KW Reference proteome; Signal.
FT SIGNAL 1..21
FT /evidence="ECO:0000255"
FT CHAIN 22..531
FT /note="Beta-hexosaminidase subunit beta"
FT /id="PRO_0000012007"
FT ACT_SITE 329
FT /note="Proton donor"
FT /evidence="ECO:0000250"
FT CARBOHYD 120
FT /note="N-linked (GlcNAc...) asparagine"
FT /evidence="ECO:0000255"
FT CARBOHYD 164
FT /note="N-linked (GlcNAc...) asparagine"
FT /evidence="ECO:0000255"
FT CARBOHYD 301
FT /note="N-linked (GlcNAc...) asparagine"
FT /evidence="ECO:0000255"
FT DISULFID 67..111
FT /evidence="ECO:0000250"
FT DISULFID 283..334
FT /evidence="ECO:0000250"
FT DISULFID 508..525
FT /evidence="ECO:0000250"
SQ SEQUENCE 531 AA; 61050 MW; F55D62D6937E51C5 CRC64;
MEVLPGLLRL LAALVVAERW ARDTSGAESL GLWPLPFAVD ISPRSLHLSP NNFFFGHSPT
SKAGSSCEIL QEAFRRYYDF IFGFYKWHQG SYQLCFGTEL QQLQVHVESE CDTFPSISSN
ESYVLHVKGP EALLRANTVW GALRGLETFS QLIYQDSYGT FTVNESEIID FPRFPHRGIL
IDTGRHFLSV KTIFKTLDAM AFNKFNVLHW HIVDDQSFPY QSINFGVLSS KGSYSLSHVY
TPNDVRMVIE YARIRGIRVM PEFDTPGHSR SWGKGQKDLL TPCYRKQVLS GTFGPINPIL
NTTYNFLSKF FKEISTVFPD EFIHIGGDEV DFDCWASNSE ILQFMQEKGF SQISLNSNLC
TVFKISNMIS AMKKRPIVWQ EAFDGRDKFM PGTVVQVWKI EDYKWEQSLI TKAGFPVILS
APWYLDLISY GQDWKNYYEV EPQDFPGSDK ERKRVLGGEA CLWGEYVDAT NLTPRLWPRA
SAVGERLWSH KDVRDIHDAY SRLTIHRCRM VRRGIAAEPL FTGYCNHEHR M
