ID   VSPA_CERCE              Reviewed;          98 AA.
AC   P81038;
DT   01-NOV-1997, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1997, sequence version 1.
DT   03-AUG-2022, entry version 83.
DE   RecName: Full=Thrombin-like enzyme cerastotin;
DE            Short=SVTLE;
DE            EC=3.4.21.-;
DE   AltName: Full=Fibrinogen-clotting enzyme;
DE   AltName: Full=Snake venom serine protease;
DE            Short=SVSP;
DE   Flags: Fragment;
OS   Cerastes cerastes (Horned desert viper).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Viperidae; Viperinae; Cerastes.
OX   NCBI_TaxID=8697;
RN   [1]
RP   PROTEIN SEQUENCE, FUNCTION, ACTIVITY REGULATION, AND SUBUNIT.
RC   TISSUE=Venom;
RX   PubMed=9249017; DOI=10.1111/j.1432-1033.1997.00121.x;
RA   Marrakchi N., Barbouche R., Guermazi S., Karoui H., Bon C., el Ayeb M.;
RT   "Cerastotin, a serine protease from Cerastes cerastes venom, with platelet-
RT   aggregating and agglutinating properties.";
RL   Eur. J. Biochem. 247:121-128(1997).
CC   -!- FUNCTION: Thrombin-like snake venom serine protease that preferentially
CC       cleaves the alpha-chain of fibrinogen (FGA). Induce platelet
CC       aggregation in the presence of exogenous fibrinogen. Possesses esterase
CC       and amidolytic activities. {ECO:0000269|PubMed:9249017}.
CC   -!- ACTIVITY REGULATION: Inhibited by PMSF. {ECO:0000269|PubMed:9249017}.
CC   -!- SUBUNIT: Monomer. {ECO:0000269|PubMed:9249017}.
CC   -!- SUBCELLULAR LOCATION: Secreted.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC   -!- SIMILARITY: Belongs to the peptidase S1 family. Snake venom subfamily.
CC       {ECO:0000255|PROSITE-ProRule:PRU00274}.
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DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0004252; F:serine-type endopeptidase activity; IEA:InterPro.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   GO; GO:0006508; P:proteolysis; IEA:UniProtKB-KW.
DR   Gene3D; 2.40.10.10; -; 2.
DR   InterPro; IPR009003; Peptidase_S1_PA.
DR   InterPro; IPR043504; Peptidase_S1_PA_chymotrypsin.
DR   InterPro; IPR001314; Peptidase_S1A.
DR   InterPro; IPR001254; Trypsin_dom.
DR   InterPro; IPR018114; TRYPSIN_HIS.
DR   Pfam; PF00089; Trypsin; 1.
DR   PRINTS; PR00722; CHYMOTRYPSIN.
DR   SUPFAM; SSF50494; SSF50494; 1.
DR   PROSITE; PS00134; TRYPSIN_HIS; 1.
PE   1: Evidence at protein level;
KW   Blood coagulation cascade activating toxin; Direct protein sequencing;
KW   Glycoprotein; Hemostasis impairing toxin; Hydrolase;
KW   Platelet aggregation activating toxin; Protease; Secreted; Serine protease;
KW   Toxin.
FT   CHAIN           1..>98
FT                   /note="Thrombin-like enzyme cerastotin"
FT                   /id="PRO_0000088736"
FT   DOMAIN          1..>98
FT                   /note="Peptidase S1"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00274"
FT   ACT_SITE        41
FT                   /note="Charge relay system"
FT                   /evidence="ECO:0000250"
FT   ACT_SITE        85
FT                   /note="Charge relay system"
FT                   /evidence="ECO:0000250"
FT   CARBOHYD        94
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   NON_TER         98
SQ   SEQUENCE   98 AA;  11168 MW;  36AF696ABF074012 CRC64;
     VIGGAECNIN EHRSLVLLYY SSRLFGGGTL INKEWVLSAA HCDGENMKII YXXXXXXXXX
     XKDRQIRVAK KYFCRDRKKS VIDKDIMLIK KPVNGSTH