ID   VSPA1_CROAT             Reviewed;          21 AA.
AC   Q9PRW4; Q9PS55;
DT   05-APR-2011, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-2000, sequence version 1.
DT   03-AUG-2022, entry version 37.
DE   RecName: Full=Alpha-fibrinogenase A1;
DE            EC=3.4.21.-;
DE   AltName: Full=Snake venom serine protease;
DE            Short=SVSP;
DE   Flags: Fragment;
OS   Crotalus atrox (Western diamondback rattlesnake).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Viperidae; Crotalinae; Crotalus.
OX   NCBI_TaxID=8730;
RN   [1]
RP   PROTEIN SEQUENCE, FUNCTION, ACTIVITY REGULATION, SUBUNIT, SUBCELLULAR
RP   LOCATION, AND TISSUE SPECIFICITY.
RC   TISSUE=Venom;
RX   PubMed=8024586; DOI=10.1006/bbrc.1994.1861;
RA   Hung C.C., Chiou S.H.;
RT   "Isolation of multiple isoforms of alpha-fibrinogenase from the Western
RT   diamondback rattlesnake, Crotalus atrox: N-terminal sequence homology with
RT   ancrod, an antithrombotic agent from Malayan viper.";
RL   Biochem. Biophys. Res. Commun. 201:1414-1423(1994).
RN   [2]
RP   PROTEIN SEQUENCE OF 1-20, ACTIVITY REGULATION, AND SUBUNIT.
RC   TISSUE=Venom;
RX   PubMed=1616487;
RA   Chiou S.H., Hung C.C., Lin C.W.;
RT   "Isolation of a crotalase-like protease with alpha-fibrinogenase activity
RT   from the Western diamondback rattlesnake, Crotalus atrox.";
RL   Biochem. Int. 26:105-112(1992).
RN   [3]
RP   PROTEIN SEQUENCE OF 1-15, AND IDENTIFICATION BY MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=19371136; DOI=10.1021/pr900249q;
RA   Calvete J.J., Fasoli E., Sanz L., Boschetti E., Righetti P.G.;
RT   "Exploring the venom proteome of the western diamondback rattlesnake,
RT   Crotalus atrox, via snake venomics and combinatorial peptide ligand library
RT   approaches.";
RL   J. Proteome Res. 8:3055-3067(2009).
CC   -!- FUNCTION: Snake venom serine protease that completely cleaves
CC       fibrinogen Aalpha chain (FGA), partially cleaves Bbeta chain (FGB) and
CC       has no activity on gamma chain. Is more potent that A2 and A3 alpha-
CC       fibrinogenases. Very active within 5 minutes.
CC       {ECO:0000269|PubMed:8024586}.
CC   -!- ACTIVITY REGULATION: Inhibited by PMSF, bovine aprotinin (APR), and
CC       soybean trypsin inhibitor (STI). Is not inhibited by EDTA, beta-
CC       mercaptoethanol, and high temperature (85 degrees Celsius).
CC       {ECO:0000269|PubMed:1616487, ECO:0000269|PubMed:8024586}.
CC   -!- SUBUNIT: Monomer. {ECO:0000269|PubMed:1616487,
CC       ECO:0000269|PubMed:8024586}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:8024586}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000269|PubMed:8024586}.
CC   -!- SIMILARITY: Belongs to the peptidase S1 family. Snake venom subfamily.
CC       {ECO:0000255|PROSITE-ProRule:PRU00274}.
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DR   PIR; A45655; A45655.
DR   PIR; PC2214; PC2214.
DR   AlphaFoldDB; Q9PRW4; -.
DR   GO; GO:0005615; C:extracellular space; IDA:UniProtKB.
DR   GO; GO:0004252; F:serine-type endopeptidase activity; IDA:UniProtKB.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   GO; GO:0006508; P:proteolysis; IEA:UniProtKB-KW.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Fibrinogenolytic toxin;
KW   Hemostasis impairing toxin; Hydrolase; Protease; Secreted; Serine protease;
KW   Toxin.
FT   CHAIN           1..>21
FT                   /note="Alpha-fibrinogenase A1"
FT                   /id="PRO_0000406904"
FT   DISULFID        7..?
FT   CONFLICT        14
FT                   /note="S -> F (in Ref. 2; AA sequence)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        19
FT                   /note="F -> Y (in Ref. 2; AA sequence)"
FT                   /evidence="ECO:0000305"
FT   NON_TER         21
SQ   SEQUENCE   21 AA;  2289 MW;  F609FB7812F343EF CRC64;
     VIGGDECNIN EHRSLVAIFD S