ID   OVOS_ANAPL              Reviewed;          32 AA.
AC   P20739;
DT   01-FEB-1991, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1991, sequence version 1.
DT   25-MAY-2022, entry version 80.
DE   RecName: Full=Ovostatin;
DE   AltName: Full=Ovomacroglobulin;
DE   Flags: Fragment;
OS   Anas platyrhynchos (Mallard) (Anas boschas).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Archelosauria; Archosauria; Dinosauria; Saurischia; Theropoda;
OC   Coelurosauria; Aves; Neognathae; Galloanserae; Anseriformes; Anatidae;
OC   Anatinae; Anas.
OX   NCBI_TaxID=8839;
RN   [1]
RP   PROTEIN SEQUENCE.
RX   PubMed=3653403; DOI=10.1016/0014-5793(87)80196-5;
RA   Nagase H., Brew K.;
RT   "Amino acid sequence of a 32-residue region around the thiol ester site in
RT   duck ovostatin.";
RL   FEBS Lett. 222:83-88(1987).
CC   -!- FUNCTION: Is able to inhibit all four classes of proteinases by a
CC       unique 'trapping' mechanism. This protein has a peptide stretch, called
CC       the 'bait region' which contains specific cleavage sites for different
CC       proteinases. When a proteinase cleaves the bait region, a
CC       conformational change is induced in the protein which traps the
CC       proteinase. The entrapped enzyme remains active against low molecular
CC       weight substrates (activity against high molecular weight substrates is
CC       greatly reduced). Following cleavage in the bait region a thioester
CC       bond is hydrolyzed and mediates the covalent binding of the protein to
CC       the proteinase.
CC   -!- SUBUNIT: Homotetramer, which consists of two pairs of disulfide-linked
CC       chains.
CC   -!- SUBCELLULAR LOCATION: Secreted.
CC   -!- SIMILARITY: Belongs to the protease inhibitor I39 (alpha-2-
CC       macroglobulin) family. {ECO:0000305}.
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DR   PIR; S00121; S00121.
DR   AlphaFoldDB; P20739; -.
DR   GO; GO:0005615; C:extracellular space; IEA:InterPro.
DR   GO; GO:0004867; F:serine-type endopeptidase inhibitor activity; IEA:UniProtKB-KW.
DR   InterPro; IPR011626; Alpha-macroglobulin_TED.
DR   InterPro; IPR019742; MacrogloblnA2_CS.
DR   InterPro; IPR008930; Terpenoid_cyclase/PrenylTrfase.
DR   Pfam; PF07678; TED_complement; 1.
DR   SUPFAM; SSF48239; SSF48239; 1.
DR   PROSITE; PS00477; ALPHA_2_MACROGLOBULIN; 1.
PE   1: Evidence at protein level;
KW   Bait region; Direct protein sequencing; Disulfide bond; Protease inhibitor;
KW   Secreted; Serine protease inhibitor; Thioester bond.
FT   CHAIN           <1..>32
FT                   /note="Ovostatin"
FT                   /id="PRO_0000093794"
FT   CROSSLNK        27..30
FT                   /note="Isoglutamyl cysteine thioester (Cys-Gln)"
FT                   /evidence="ECO:0000269|PubMed:3653403"
FT   NON_TER         1
FT   NON_TER         32
SQ   SEQUENCE   32 AA;  3472 MW;  7795D67965E28581 CRC64;
     ASFSVVGDIM GTSMQNLHQL LQMPFGCGEQ NM