ID   VKTCT_OPHHA             Reviewed;          83 AA.
AC   B6RLX2;
DT   16-JUN-2009, integrated into UniProtKB/Swiss-Prot.
DT   16-DEC-2008, sequence version 1.
DT   25-MAY-2022, entry version 34.
DE   RecName: Full=Kunitz-type serine protease inhibitor TCI;
DE   AltName: Full=Trypsin and chymotrypsin bi-functional serine protease inhibitor;
DE            Short=OH-TCI;
DE   Flags: Precursor;
OS   Ophiophagus hannah (King cobra) (Naja hannah).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Elapidae; Elapinae; Ophiophagus.
OX   NCBI_TaxID=8665;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 26-45, FUNCTION, MASS
RP   SPECTROMETRY, AND SUBCELLULAR LOCATION.
RC   TISSUE=Venom, and Venom gland;
RX   PubMed=18582511; DOI=10.1016/j.peptides.2008.05.025;
RA   He Y.-Y., Liu S.-B., Lee W.-H., Qian J.-Q., Zhang Y.;
RT   "Isolation, expression and characterization of a novel dual serine protease
RT   inhibitor, OH-TCI, from king cobra venom.";
RL   Peptides 29:1692-1699(2008).
RN   [2]
RP   IDENTIFICATION BY MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=24297900; DOI=10.1073/pnas.1314702110;
RA   Vonk F.J., Casewell N.R., Henkel C.V., Heimberg A.M., Jansen H.J.,
RA   McCleary R.J., Kerkkamp H.M., Vos R.A., Guerreiro I., Calvete J.J.,
RA   Wuster W., Woods A.E., Logan J.M., Harrison R.A., Castoe T.A.,
RA   de Koning A.P., Pollock D.D., Yandell M., Calderon D., Renjifo C.,
RA   Currier R.B., Salgado D., Pla D., Sanz L., Hyder A.S., Ribeiro J.M.,
RA   Arntzen J.W., van den Thillart G.E., Boetzer M., Pirovano W., Dirks R.P.,
RA   Spaink H.P., Duboule D., McGlinn E., Kini R.M., Richardson M.K.;
RT   "The king cobra genome reveals dynamic gene evolution and adaptation in the
RT   snake venom system.";
RL   Proc. Natl. Acad. Sci. U.S.A. 110:20651-20656(2013).
CC   -!- FUNCTION: Serine protease inhibitor that strongly inhibits chymotrypsin
CC       (Ki=84.6 nM) and trypsin (Ki=391 nM). {ECO:0000269|PubMed:18582511}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:18582511}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:18582511}.
CC   -!- MASS SPECTROMETRY: Mass=6339; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:18582511};
CC   -!- SIMILARITY: Belongs to the venom Kunitz-type family. {ECO:0000305}.
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DR   EMBL; EU246692; ABY74980.1; -; mRNA.
DR   AlphaFoldDB; B6RLX2; -.
DR   SMR; B6RLX2; -.
DR   MEROPS; I02.055; -.
DR   TopDownProteomics; B6RLX2; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0004867; F:serine-type endopeptidase inhibitor 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; Protease inhibitor; Secreted;
KW   Serine protease inhibitor; Signal.
FT   SIGNAL          1..25
FT                   /evidence="ECO:0000269|PubMed:18582511"
FT   CHAIN           26..83
FT                   /note="Kunitz-type serine protease inhibitor TCI"
FT                   /id="PRO_0000377473"
FT   DOMAIN          31..81
FT                   /note="BPTI/Kunitz inhibitor"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   SITE            41..42
FT                   /note="Reactive bond for trypsin"
FT                   /evidence="ECO:0000250"
FT   DISULFID        31..81
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   DISULFID        40..64
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   DISULFID        56..77
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
SQ   SEQUENCE   83 AA;  8983 MW;  BB14890B90D31BDC CRC64;
     MSSGRLLLLL GLLTLWAELT PVSGLGRPKF CELPAVSGFC KAYIPSFYYN PDASACQKFI
     YGGCGGNANK FKTIEECHRT CVG