ID   VKTB1_DABSI             Reviewed;          84 AA.
AC   A8Y7P1;
DT   16-JUN-2009, integrated into UniProtKB/Swiss-Prot.
DT   15-JAN-2008, sequence version 1.
DT   25-MAY-2022, entry version 43.
DE   RecName: Full=Kunitz-type serine protease inhibitor B1;
DE   AltName: Full=BBPTI-1;
DE            Short=BPTI-1;
DE   AltName: Full=Trypsin inhibitor 1;
DE   AltName: Full=Trypsin inhibitor B1;
DE   Flags: Precursor;
OS   Daboia siamensis (Eastern Russel's viper) (Daboia russelii siamensis).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Viperidae; Viperinae; Daboia.
OX   NCBI_TaxID=343250;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 25-47, FUNCTION, AND MASS
RP   SPECTROMETRY.
RC   STRAIN=Myanmar; TISSUE=Venom, and Venom gland;
RX   PubMed=23428970; DOI=10.1016/j.peptides.2013.02.009;
RA   Guo C.T., McClean S., Shaw C., Rao P.F., Ye M.Y., Bjourson A.J.;
RT   "Purification, characterization and molecular cloning of chymotrypsin
RT   inhibitor peptides from the venom of Burmese Daboia russelli siamensis.";
RL   Peptides 43:126-132(2013).
CC   -!- FUNCTION: Serine protease inhibitor that has activity against
CC       chymotrypsin (Ki=4.77 nM) but not against trypsin.
CC       {ECO:0000269|PubMed:23428970}.
CC   -!- SUBCELLULAR LOCATION: Secreted.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC   -!- MASS SPECTROMETRY: Mass=6874.2; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:23428970};
CC   -!- SIMILARITY: Belongs to the venom Kunitz-type family. {ECO:0000305}.
CC   ---------------------------------------------------------------------------
CC   Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms
CC   Distributed under the Creative Commons Attribution (CC BY 4.0) License
CC   ---------------------------------------------------------------------------
DR   EMBL; AM411368; CAL69609.1; -; mRNA.
DR   AlphaFoldDB; A8Y7P1; -.
DR   SMR; A8Y7P1; -.
DR   MEROPS; I02.062; -.
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..24
FT                   /evidence="ECO:0000269|PubMed:23428970"
FT   CHAIN           25..84
FT                   /note="Kunitz-type serine protease inhibitor B1"
FT                   /id="PRO_5000284434"
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 chymotrypsin"
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   84 AA;  9318 MW;  93CE34ADDA8E2F12 CRC64;
     MSSGGLLLLL GLLTLWAELT PISGHDRPKF CYLPADPGEC LAHMRSFYYD SESKKCKEFI
     YGGCHGNANK FPSRDKCRQT CGGK