ID   VKTHB_DENPO             Reviewed;          57 AA.
AC   P00983;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   21-JUL-1986, sequence version 1.
DT   25-MAY-2022, entry version 95.
DE   RecName: Full=Kunitz-type serine protease inhibitor homolog dendrotoxin B;
DE            Short=DTX-B;
DE   AltName: Full=Venom basic protease inhibitor B;
OS   Dendroaspis polylepis polylepis (Black mamba).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Elapidae; Elapinae; Dendroaspis.
OX   NCBI_TaxID=8620;
RN   [1]
RP   PROTEIN SEQUENCE.
RC   TISSUE=Venom;
RX   PubMed=7309000; DOI=10.1515/bchm2.1981.362.2.1377;
RA   Strydom D.J., Joubert F.J.;
RT   "The amino acid sequence of a weak trypsin inhibitor B from Dendroaspis
RT   polylepis polylepis (black mamba) venom.";
RL   Hoppe-Seyler's Z. Physiol. Chem. 362:1377-1384(1981).
CC   -!- FUNCTION: Highly selective blocker of voltage-gated potassium channels
CC       (Kv). Inhibits trypsin weakly.
CC   -!- SUBCELLULAR LOCATION: Secreted.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC   -!- SIMILARITY: Belongs to the venom Kunitz-type family. {ECO:0000305}.
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DR   PIR; A01214; TIEPVB.
DR   AlphaFoldDB; P00983; -.
DR   SMR; P00983; -.
DR   MEROPS; I02.056; -.
DR   PRIDE; P00983; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0015459; F:potassium channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0004867; F:serine-type endopeptidase inhibitor activity; IEA:InterPro.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   CDD; cd00109; KU; 1.
DR   Gene3D; 4.10.410.10; -; 1.
DR   InterPro; IPR002223; Kunitz_BPTI.
DR   InterPro; IPR036880; Kunitz_BPTI_sf.
DR   InterPro; IPR020901; Prtase_inh_Kunz-CS.
DR   Pfam; PF00014; Kunitz_BPTI; 1.
DR   PRINTS; PR00759; BASICPTASE.
DR   SMART; SM00131; KU; 1.
DR   SUPFAM; SSF57362; SSF57362; 1.
DR   PROSITE; PS00280; BPTI_KUNITZ_1; 1.
DR   PROSITE; PS50279; BPTI_KUNITZ_2; 1.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW   Neurotoxin; Potassium channel impairing toxin; Secreted; Toxin;
KW   Voltage-gated potassium channel impairing toxin.
FT   CHAIN           1..57
FT                   /note="Kunitz-type serine protease inhibitor homolog
FT                   dendrotoxin B"
FT                   /id="PRO_0000155435"
FT   DOMAIN          5..55
FT                   /note="BPTI/Kunitz inhibitor"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   DISULFID        5..55
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   DISULFID        14..38
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   DISULFID        30..51
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
SQ   SEQUENCE   57 AA;  6476 MW;  5090338CD360800C CRC64;
     RPYACELIVA AGPCMFFISA FYYSKGANKC YPFTYSGCRG NANRFKTIEE CRRTCVV