ID   A1AT4_HORSE             Reviewed;          43 AA.
AC   P38031;
DT   01-OCT-1994, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-1994, sequence version 1.
DT   25-MAY-2022, entry version 66.
DE   RecName: Full=Alpha-1-antiproteinase 4;
DE   AltName: Full=Alpha-1-antitrypsin 4;
DE   AltName: Full=Alpha-1-proteinase inhibitor 4;
DE   AltName: Full=SPI4;
DE   Flags: Fragments;
OS   Equus caballus (Horse).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC   Eutheria; Laurasiatheria; Perissodactyla; Equidae; Equus.
OX   NCBI_TaxID=9796;
RN   [1]
RP   PROTEIN SEQUENCE.
RC   TISSUE=Plasma;
RX   PubMed=1772402; DOI=10.1007/bf02399689;
RA   Patterson S.D., Bell K., Shaw D.C.;
RT   "The equine major plasma serpin multigene family: partial characterization
RT   including sequence of the reactive-site regions.";
RL   Biochem. Genet. 29:477-499(1991).
RN   [2]
RP   STRUCTURE OF CARBOHYDRATES.
RX   PubMed=2111994;
RA   Patterson S.D., Bell K.;
RT   "The carbohydrate side chains of the major plasma serpins of horse and
RT   wallaby: analyses of enzymatic and chemically treated (including 'Smith
RT   degradation') protein blots by lectin binding.";
RL   Biochem. Int. 20:429-436(1990).
CC   -!- SUBCELLULAR LOCATION: Secreted.
CC   -!- TISSUE SPECIFICITY: Plasma.
CC   -!- DOMAIN: The reactive center loop (RCL) extends out from the body of the
CC       protein and directs binding to the target protease. The protease
CC       cleaves the serpin at the reactive site within the RCL, establishing a
CC       covalent linkage between the serpin reactive site and the active site
CC       of the protease. The resulting inactive serpin-protease complex is
CC       highly stable (By similarity). {ECO:0000250}.
CC   -!- PTM: N-glycosylated with carbohydrates having biantennary side chains.
CC   -!- SIMILARITY: Belongs to the serpin family. {ECO:0000305}.
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DR   PIR; D61219; D61219.
DR   AlphaFoldDB; P38031; -.
DR   PeptideAtlas; P38031; -.
DR   Proteomes; UP000002281; Unplaced.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0004867; F:serine-type endopeptidase inhibitor activity; IEA:UniProtKB-KW.
DR   GO; GO:0006953; P:acute-phase response; IEA:UniProtKB-KW.
DR   PROSITE; PS00284; SERPIN; 1.
PE   1: Evidence at protein level;
KW   Acute phase; Direct protein sequencing; Glycoprotein; Protease inhibitor;
KW   Reference proteome; Secreted; Serine protease inhibitor.
FT   CHAIN           1..>43
FT                   /note="Alpha-1-antiproteinase 4"
FT                   /id="PRO_0000094094"
FT   SITE            23..24
FT                   /note="Reactive bond"
FT   NON_CONS        19..20
FT                   /evidence="ECO:0000305"
FT   NON_TER         43
SQ   SEQUENCE   43 AA;  4925 MW;  18E9430C1F4AA87A CRC64;
     EDLQGTAVQE RSAKASDEEE AIRTLLLTNV EFNRPFVLSI YDR