ID   ISK1_PIG                Reviewed;          56 AA.
AC   P00998;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   21-JUL-1986, sequence version 1.
DT   24-JAN-2024, entry version 142.
DE   RecName: Full=Serine protease inhibitor Kazal-type 1 {ECO:0000250|UniProtKB:P09036};
DE   AltName: Full=Pancreatic secretory trypsin inhibitor {ECO:0000303|PubMed:5466061};
GN   Name=SPINK1; Synonyms=PSTI;
OS   Sus scrofa (Pig).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC   Eutheria; Laurasiatheria; Artiodactyla; Suina; Suidae; Sus.
OX   NCBI_TaxID=9823;
RN   [1]
RP   PROTEIN SEQUENCE, FUNCTION, AND SUBCELLULAR LOCATION.
RX   PubMed=5466061; DOI=10.1111/j.1432-1033.1970.tb01071.x;
RA   Tschesche H., Wachter E.;
RT   "The structure of the porcine pancreatic secretory trypsin inhibitor. I. A
RT   sequence determination by Edman degradation and mass spectral
RT   identification of the p-bromophenyl-thiohydantoins.";
RL   Eur. J. Biochem. 16:187-198(1970).
RN   [2]
RP   PROTEIN SEQUENCE.
RX   PubMed=5103069; DOI=10.1016/s0021-9258(19)77211-1;
RA   Bartelt D.C., Greene L.J.;
RT   "The primary structure of the porcine pancreatic secretory trypsin
RT   inhibitor. I. Amino acid sequence of the reduced S-aminoethylated
RT   protein.";
RL   J. Biol. Chem. 246:2218-2229(1971).
RN   [3]
RP   DISULFIDE BONDS.
RX   PubMed=4672150;
RA   Tschesche H., Schneider M., Reidel G., Klein H.;
RT   "Disulfide bridges of the secretory trypsin inhibitor from procine pancreas
RT   and the degradation of covalent structure during the temporary
RT   inhibition.";
RL   Hoppe-Seyler's Z. Physiol. Chem. 353:763-764(1972).
RN   [4]
RP   PROTEIN SEQUENCE OF A SECOND INHIBITOR.
RX   PubMed=5531651;
RA   Tschesche H., Wachter E.;
RT   "Trypsin inhibitors. VII. Primary structure of the specific trypsin
RT   inhibitor II (Kazal-type) from porcine pancreas. Sequence analysis with
RT   mass spectrometry identification of the p-bromophenylthio-hydantoins from
RT   the Edman degradation.";
RL   Hoppe-Seyler's Z. Physiol. Chem. 351:1449-1459(1970).
RN   [5]
RP   X-RAY CRYSTALLOGRAPHY (1.8 ANGSTROMS).
RX   PubMed=7169635; DOI=10.1016/0022-2836(82)90550-2;
RA   Bolognesi M., Gatti G., Menegatti E., Guarneri M., Marquart M.,
RA   Papamokos E., Huber R.;
RT   "Three-dimensional structure of the complex between pancreatic secretory
RT   trypsin inhibitor (Kazal type) and trypsinogen at 1.8-A resolution.
RT   Structure solution, crystallographic refinement and preliminary structural
RT   interpretation.";
RL   J. Mol. Biol. 162:839-868(1982).
CC   -!- FUNCTION: Serine protease inhibitor which exhibits anti-trypsin
CC       activity (PubMed:5466061). In the pancreas, protects against trypsin-
CC       catalyzed premature activation of zymogens (By similarity).
CC       {ECO:0000250|UniProtKB:P09036, ECO:0000269|PubMed:5466061}.
CC   -!- FUNCTION: In the male reproductive tract, binds to sperm heads where it
CC       modulates sperm capacitance by inhibiting calcium uptake and nitrogen
CC       oxide (NO) production. {ECO:0000250|UniProtKB:P09036}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:5466061,
CC       ECO:0000269|PubMed:7169635}.
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DR   PIR; A91174; TIPG.
DR   PDB; 1TGS; X-ray; 1.80 A; I=1-56.
DR   PDBsum; 1TGS; -.
DR   AlphaFoldDB; P00998; -.
DR   SMR; P00998; -.
DR   MINT; P00998; -.
DR   STRING; 9823.ENSSSCP00000058066; -.
DR   MEROPS; I01.011; -.
DR   PaxDb; 9823-ENSSSCP00000022179; -.
DR   PeptideAtlas; P00998; -.
DR   Ensembl; ENSSSCT00005038608.1; ENSSSCP00005023696.1; ENSSSCG00005024363.1.
DR   eggNOG; KOG3649; Eukaryota.
DR   HOGENOM; CLU_169765_6_0_1; -.
DR   InParanoid; P00998; -.
DR   EvolutionaryTrace; P00998; -.
DR   Proteomes; UP000008227; Unplaced.
DR   Proteomes; UP000314985; Unplaced.
DR   Proteomes; UP000694570; Unplaced.
DR   Proteomes; UP000694571; Unplaced.
DR   Proteomes; UP000694720; Unplaced.
DR   Proteomes; UP000694722; Unplaced.
DR   Proteomes; UP000694723; Unplaced.
DR   Proteomes; UP000694724; Unplaced.
DR   Proteomes; UP000694725; Unplaced.
DR   Proteomes; UP000694726; Unplaced.
DR   Proteomes; UP000694727; Unplaced.
DR   Proteomes; UP000694728; 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   CDD; cd01327; KAZAL_PSTI; 1.
DR   Gene3D; 3.30.60.30; -; 1.
DR   InterPro; IPR002350; Kazal_dom.
DR   InterPro; IPR036058; Kazal_dom_sf.
DR   InterPro; IPR001239; Prot_inh_Kazal-m.
DR   PANTHER; PTHR21312; SERINE PROTEASE INHIBITOR; 1.
DR   PANTHER; PTHR21312:SF27; SERINE PROTEASE INHIBITOR KAZAL-TYPE 1; 1.
DR   Pfam; PF00050; Kazal_1; 1.
DR   PRINTS; PR00290; KAZALINHBTR.
DR   SMART; SM00280; KAZAL; 1.
DR   SUPFAM; SSF100895; Kazal-type serine protease inhibitors; 1.
DR   PROSITE; PS00282; KAZAL_1; 1.
DR   PROSITE; PS51465; KAZAL_2; 1.
DR   Genevisible; P00998; SS.
PE   1: Evidence at protein level;
KW   3D-structure; Direct protein sequencing; Disulfide bond;
KW   Protease inhibitor; Reference proteome; Secreted;
KW   Serine protease inhibitor.
FT   CHAIN           1..56
FT                   /note="Serine protease inhibitor Kazal-type 1"
FT                   /id="PRO_0000073027"
FT   DOMAIN          3..56
FT                   /note="Kazal-like"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00798"
FT   SITE            18..19
FT                   /note="Reactive bond for trypsin"
FT                   /evidence="ECO:0000250|UniProtKB:P09036,
FT                   ECO:0000255|PROSITE-ProRule:PRU00798"
FT   SITE            20..21
FT                   /note="Necessary for sperm binding"
FT                   /evidence="ECO:0000250|UniProtKB:P09036"
FT   DISULFID        9..38
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00798,
FT                   ECO:0000269|PubMed:4672150"
FT   DISULFID        16..35
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00798,
FT                   ECO:0000269|PubMed:4672150"
FT   DISULFID        24..56
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00798,
FT                   ECO:0000269|PubMed:4672150"
FT   VARIANT         1..4
FT                   /note="Missing (in a second inhibitor)"
FT   STRAND          12..17
FT                   /evidence="ECO:0007829|PDB:1TGS"
FT   STRAND          23..25
FT                   /evidence="ECO:0007829|PDB:1TGS"
FT   STRAND          30..33
FT                   /evidence="ECO:0007829|PDB:1TGS"
FT   HELIX           34..42
FT                   /evidence="ECO:0007829|PDB:1TGS"
FT   STRAND          50..54
FT                   /evidence="ECO:0007829|PDB:1TGS"
SQ   SEQUENCE   56 AA;  6023 MW;  39A3649DADF16D25 CRC64;
     TSPQREATCT SEVSGCPKIY NPVCGTDGIT YSNECVLCSE NKKRQTPVLI QKSGPC
//