UniProt functional annotation for P03951



	UniProt functional annotation for P03951

UniProt code: P03951.

Organism: Homo sapiens (Human).

Taxonomy: Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo.

Function: Factor XI triggers the middle phase of the intrinsic pathway of blood coagulation by activating factor IX.

Catalytic activity: Reaction=Selective cleavage of Arg-|-Ala and Arg-|-Val bonds in factor IX to form factor IXa.; EC=3.4.21.27;

Activity regulation: Inhibited by SERPINA5. {ECO:0000269|PubMed:2844223}.

Subunit: Homodimer; disulfide-linked. Forms a heterodimer with SERPINA5. After activation the heavy and light chains are also linked by a disulfide bond. {ECO:0000269|PubMed:18510371, ECO:0000269|PubMed:1998667}.

Subcellular location: Secreted.

Tissue specificity: Isoform 2 is produced by platelets and megakaryocytes but absent from other blood cells.

Ptm: N-glycosylated on both chains. N-glycosylated sites mainly consist of nonfucosylated sialylated biantennary (in high abundance) and/or triantennary (in low abundance) complex structures. Glycosylation at Asn-163 uses a rare non-canonical Asn-X-Cys glycosite. {ECO:0000269|PubMed:25092234}.

Ptm: Activated by factor XIIa (or XII), which cleaves each polypeptide after Arg-387 into the light chain, which contains the active site, and the heavy chain, which associates with high molecular weight (HMW) kininogen.

Disease: Factor XI deficiency (FA11D) [MIM:612416]: A hemorrhagic disease characterized by reduced levels and activity of factor XI resulting in moderate bleeding symptoms, usually occurring after trauma or surgery. Patients usually do not present spontaneous bleeding but women can present with menorrhagia. Hemorrhages are usually moderate. {ECO:0000269|PubMed:10027710, ECO:0000269|PubMed:10606881, ECO:0000269|PubMed:11895778, ECO:0000269|PubMed:15026311, ECO:0000269|PubMed:15180874, ECO:0000269|PubMed:1547342, ECO:0000269|PubMed:15953011, ECO:0000269|PubMed:16607084, ECO:0000269|PubMed:18005151, ECO:0000269|PubMed:21457405, ECO:0000269|PubMed:21668437, ECO:0000269|PubMed:21999818, ECO:0000269|PubMed:22016685, ECO:0000269|PubMed:22159456, ECO:0000269|PubMed:22322133, ECO:0000269|PubMed:25158988, ECO:0000269|PubMed:2813350, ECO:0000269|PubMed:7669672, ECO:0000269|PubMed:7888672, ECO:0000269|PubMed:9401068, ECO:0000269|PubMed:9787168}. Note=The disease is caused by variants affecting the gene represented in this entry.

Similarity: Belongs to the peptidase S1 family. Plasma kallikrein subfamily. {ECO:0000255|PROSITE-ProRule:PRU00274}.

Annotations taken from UniProtKB at the EBI.


Organism:		Homo sapiens (Human).
Taxonomy:		Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo.



Function:		Factor XI triggers the middle phase of the intrinsic pathway of blood coagulation by activating factor IX.


Catalytic activity:		Reaction=Selective cleavage of Arg-\|-Ala and Arg-\|-Val bonds in factor IX to form factor IXa.; EC=3.4.21.27;
Activity regulation:		Inhibited by SERPINA5. {ECO:0000269\|PubMed:2844223}.
Subunit:		Homodimer; disulfide-linked. Forms a heterodimer with SERPINA5. After activation the heavy and light chains are also linked by a disulfide bond. {ECO:0000269\|PubMed:18510371, ECO:0000269\|PubMed:1998667}.
Subcellular location:		Secreted.
Tissue specificity:		Isoform 2 is produced by platelets and megakaryocytes but absent from other blood cells.
Ptm:		N-glycosylated on both chains. N-glycosylated sites mainly consist of nonfucosylated sialylated biantennary (in high abundance) and/or triantennary (in low abundance) complex structures. Glycosylation at Asn-163 uses a rare non-canonical Asn-X-Cys glycosite. {ECO:0000269\|PubMed:25092234}.
Ptm:		Activated by factor XIIa (or XII), which cleaves each polypeptide after Arg-387 into the light chain, which contains the active site, and the heavy chain, which associates with high molecular weight (HMW) kininogen.
Disease:		Factor XI deficiency (FA11D) [MIM:612416]: A hemorrhagic disease characterized by reduced levels and activity of factor XI resulting in moderate bleeding symptoms, usually occurring after trauma or surgery. Patients usually do not present spontaneous bleeding but women can present with menorrhagia. Hemorrhages are usually moderate. {ECO:0000269\|PubMed:10027710, ECO:0000269\|PubMed:10606881, ECO:0000269\|PubMed:11895778, ECO:0000269\|PubMed:15026311, ECO:0000269\|PubMed:15180874, ECO:0000269\|PubMed:1547342, ECO:0000269\|PubMed:15953011, ECO:0000269\|PubMed:16607084, ECO:0000269\|PubMed:18005151, ECO:0000269\|PubMed:21457405, ECO:0000269\|PubMed:21668437, ECO:0000269\|PubMed:21999818, ECO:0000269\|PubMed:22016685, ECO:0000269\|PubMed:22159456, ECO:0000269\|PubMed:22322133, ECO:0000269\|PubMed:25158988, ECO:0000269\|PubMed:2813350, ECO:0000269\|PubMed:7669672, ECO:0000269\|PubMed:7888672, ECO:0000269\|PubMed:9401068, ECO:0000269\|PubMed:9787168}. Note=The disease is caused by variants affecting the gene represented in this entry.
Similarity:		Belongs to the peptidase S1 family. Plasma kallikrein subfamily. {ECO:0000255\|PROSITE-ProRule:PRU00274}.