ID   CATB_COTJA              Reviewed;          48 AA.
AC   P81494;
DT   15-DEC-1998, integrated into UniProtKB/Swiss-Prot.
DT   15-DEC-1998, sequence version 1.
DT   03-AUG-2022, entry version 87.
DE   RecName: Full=Cathepsin B;
DE            EC=3.4.22.1;
DE   AltName: Full=Cathepsin B1;
DE   Contains:
DE     RecName: Full=Cathepsin B light chain;
DE   Contains:
DE     RecName: Full=Cathepsin B heavy chain;
DE   Flags: Fragments;
GN   Name=CTSB;
OS   Coturnix japonica (Japanese quail) (Coturnix coturnix japonica).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Archelosauria; Archosauria; Dinosauria; Saurischia; Theropoda;
OC   Coelurosauria; Aves; Neognathae; Galloanserae; Galliformes; Phasianidae;
OC   Perdicinae; Coturnix.
OX   NCBI_TaxID=93934;
RN   [1]
RP   PROTEIN SEQUENCE.
RX   PubMed=9418005; DOI=10.1016/s0305-0491(97)00034-5;
RA   Gerhartz B., Auerswald E.A., Mentele R., Fritz H., Machleidt W., Kolb H.J.,
RA   Wittmann J.;
RT   "Proteolytic enzymes in yolk-sac membrane of quail egg. Purification and
RT   enzymatic characterisation.";
RL   Comp. Biochem. Physiol. 118B:159-166(1997).
CC   -!- FUNCTION: Thiol protease which is believed to participate in
CC       intracellular degradation and turnover of proteins. Has also been
CC       implicated in tumor invasion and metastasis.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=Hydrolysis of proteins with broad specificity for peptide
CC         bonds. Preferentially cleaves -Arg-Arg-|-Xaa bonds in small molecule
CC         substrates (thus differing from cathepsin L). In addition to being an
CC         endopeptidase, shows peptidyl-dipeptidase activity, liberating C-
CC         terminal dipeptides.; EC=3.4.22.1;
CC   -!- SUBUNIT: Dimer of a heavy chain and a light chain cross-linked by a
CC       disulfide bond.
CC   -!- SUBCELLULAR LOCATION: Lysosome.
CC   -!- SIMILARITY: Belongs to the peptidase C1 family. {ECO:0000255|PROSITE-
CC       ProRule:PRU10088, ECO:0000255|PROSITE-ProRule:PRU10089,
CC       ECO:0000255|PROSITE-ProRule:PRU10090}.
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DR   AlphaFoldDB; P81494; -.
DR   SMR; P81494; -.
DR   Proteomes; UP000694412; Unplaced.
DR   GO; GO:0005764; C:lysosome; IEA:UniProtKB-SubCell.
DR   GO; GO:0004197; F:cysteine-type endopeptidase activity; IEA:UniProtKB-EC.
DR   GO; GO:0006508; P:proteolysis; IEA:UniProtKB-KW.
DR   InterPro; IPR038765; Papain-like_cys_pep_sf.
DR   SUPFAM; SSF54001; SSF54001; 1.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Hydrolase; Lysosome; Protease;
KW   Reference proteome; Thiol protease.
FT   CHAIN           1..>25
FT                   /note="Cathepsin B"
FT                   /id="PRO_0000026162"
FT   CHAIN           1..>25
FT                   /note="Cathepsin B light chain"
FT                   /id="PRO_0000409492"
FT   CHAIN           26..>48
FT                   /note="Cathepsin B heavy chain"
FT                   /id="PRO_0000026163"
FT   NON_CONS        25..26
FT                   /evidence="ECO:0000305"
FT   NON_TER         48
SQ   SEQUENCE   48 AA;  5226 MW;  F1763CC54BF91ACC CRC64;
     LPDTFDSRKQ WPNCPTISEI RDQGSVSVEV SAEDLLSCCG FECGMGCN