Reviewed, UniProtKB/Swiss-Prot Q7LZF4 (VSP4A_CERCE)

Names and origin

Protein names	Recommended name:     Basic proteinase IVa     EC=3.4.21.74
Organism	Cerastes cerastes (Horned desert viper)
Taxonomic identifier	8697 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Lepidosauria › Squamata › Scleroglossa › Serpentes › Colubroidea › Viperidae › Viperinae › Cerastes

Protein attributes

Sequence length	15 AA.
Sequence status	Fragment.
Sequence processing	The displayed sequence is not processed.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Thrombin-like snake venom serine protease. Induces platelet aggregation. Its aggregatory activity is partially inhibited by monoclonal antibodies against GPIb and the thrombin receptor. Its ability to induce intracellular Ca2+ release is blocked by pretreating platelets with thrombin. Shows very weak coagulant activity, but can hydrolyze fibrinogen alpha-chains.
Catalytic activity	Selective cleavage of Arg-|-Xaa bond in fibrinogen, to form fibrin, and release fibrinopeptide A. The specificity of further degradation of fibrinogen varies with species origin of the enzyme.
Enzyme regulation	Inactivated by p-APMSF, leupeptin, iodoacetamide, protein kinase C inhibitor, phosphatase inhibitor, ATP and PGE1. Is insensitive to acetylsalicylic acid, ADP scavenger system, protein kinase A inhibitor and hirudin.
Subunit structure	Dimer.
Subcellular location	Secreted.
Tissue specificity	Expressed by the venom gland.
Sequence similarities	Belongs to the peptidase S1 family. Snake venom subfamily. Contains 1 peptidase S1 domain.

Ontologies

Keywords
Biological process	Blood coagulation
Cellular component	Secreted
Molecular function	Hydrolase Protease Serine protease Toxin
Technical term	Direct protein sequencing
Gene Ontology (GO)
Biological process	blood coagulation Inferred from electronic annotation. Source: UniProtKB-KW pathogenesis Inferred from electronic annotation. Source: UniProtKB-KW
Cellular component	extracellular region Inferred from electronic annotation. Source: UniProtKB-SubCell
Molecular function	serine-type peptidase activity Inferred from electronic annotation. Source: UniProtKB-KW
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Chain	1 – ›15	›15	Basic proteinase IVa		PRO_0000294992
Regions
	Domain	1 – ›15	›15	Peptidase S1
Experimental info
	Non-terminal residue	15	1

Sequences

	Sequence		Length	Mass (Da)
	Q7LZF4-1 [UniParc]. Last modified December 15, 2003. Version 1. Checksum: 0471E55327D52FDA	FASTA	15	1,638
	10 VIGGAEENIN EHRSL

References

[1]	"Characterization of a potent platelet aggregation inducer from Cerastes cerastes (Egyptian sand viper) venom." Basheer A.R., el-Asmar M.F., Soslau G. Biochim. Biophys. Acta 1250:97-109(1995) [PubMed: 7612660] [Abstract] Cited for: PROTEIN SEQUENCE. Tissue: Venom.

Cross-references

Sequence databases
PIR	S57201.
3D structure databases
ModBase	Search...
Phylogenomic databases
HOVERGEN	Q7LZF4.
Enzyme and pathway databases
BRENDA	3.4.21.74. 18553.
Family and domain databases
InterPro	IPR018114. Peptidase_S1/S6_AS. [Graphical view]
PROSITE	PS50240. TRYPSIN_DOM. Partial match. PS00134. TRYPSIN_HIS. Partial match. PS00135. TRYPSIN_SER. Partial match. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

VSP4A_CERCE

Accession

Primary (citable) accession number: Q7LZF4

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 10, 2007
Last sequence update:	December 15, 2003
Last modified:	June 16, 2009
This is version 20 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

Tox-Prot (Toxin Annotation Project)