ID   PEPA_CHICK              Reviewed;         367 AA.
AC   P00793;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   21-JUL-1986, sequence version 1.
DT   03-AUG-2022, entry version 120.
DE   RecName: Full=Pepsin A;
DE            EC=3.4.23.1;
DE   Flags: Precursor;
GN   Name=PGA;
OS   Gallus gallus (Chicken).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Archelosauria; Archosauria; Dinosauria; Saurischia; Theropoda;
OC   Coelurosauria; Aves; Neognathae; Galloanserae; Galliformes; Phasianidae;
OC   Phasianinae; Gallus.
OX   NCBI_TaxID=9031;
RN   [1]
RP   PROTEIN SEQUENCE.
RX   PubMed=6617663; DOI=10.1111/j.1432-1033.1983.tb07709.x;
RA   Baudys M., Kostka V.;
RT   "Covalent structure of chicken pepsinogen.";
RL   Eur. J. Biochem. 136:89-99(1983).
CC   -!- FUNCTION: Shows particularly broad specificity; although bonds
CC       involving phenylalanine and leucine are preferred, many others are also
CC       cleaved to some extent.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=Preferential cleavage: hydrophobic, preferably aromatic,
CC         residues in P1 and P1' positions. Cleaves 1-Phe-|-Val-2, 4-Gln-|-His-
CC         5, 13-Glu-|-Ala-14, 14-Ala-|-Leu-15, 15-Leu-|-Tyr-16, 16-Tyr-|-Leu-
CC         17, 23-Gly-|-Phe-24, 24-Phe-|-Phe-25 and 25-Phe-|-Tyr-26 bonds in the
CC         B chain of insulin.; EC=3.4.23.1; Evidence={ECO:0000255|PROSITE-
CC         ProRule:PRU10094};
CC   -!- SIMILARITY: Belongs to the peptidase A1 family. {ECO:0000305}.
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DR   AlphaFoldDB; P00793; -.
DR   SMR; P00793; -.
DR   STRING; 9031.ENSGALP00000034609; -.
DR   PaxDb; P00793; -.
DR   VEuPathDB; HostDB:geneid_395691; -.
DR   eggNOG; KOG1339; Eukaryota.
DR   InParanoid; P00793; -.
DR   Proteomes; UP000000539; Unplaced.
DR   GO; GO:0004190; F:aspartic-type endopeptidase activity; IBA:GO_Central.
DR   GO; GO:0007586; P:digestion; IEA:UniProtKB-KW.
DR   GO; GO:0006508; P:proteolysis; IBA:GO_Central.
DR   CDD; cd05478; pepsin_A; 1.
DR   Gene3D; 2.40.70.10; -; 2.
DR   InterPro; IPR001461; Aspartic_peptidase_A1.
DR   InterPro; IPR001969; Aspartic_peptidase_AS.
DR   InterPro; IPR012848; Aspartic_peptidase_N.
DR   InterPro; IPR034162; Pepsin_A.
DR   InterPro; IPR033121; PEPTIDASE_A1.
DR   InterPro; IPR021109; Peptidase_aspartic_dom_sf.
DR   PANTHER; PTHR47966; PTHR47966; 1.
DR   Pfam; PF07966; A1_Propeptide; 1.
DR   Pfam; PF00026; Asp; 1.
DR   PRINTS; PR00792; PEPSIN.
DR   SUPFAM; SSF50630; SSF50630; 1.
DR   PROSITE; PS00141; ASP_PROTEASE; 2.
DR   PROSITE; PS51767; PEPTIDASE_A1; 1.
PE   1: Evidence at protein level;
KW   Aspartyl protease; Digestion; Direct protein sequencing; Disulfide bond;
KW   Glycoprotein; Hydrolase; Protease; Reference proteome; Zymogen.
FT   PROPEP          1..42
FT                   /note="Activation peptide"
FT                   /id="PRO_0000026046"
FT   CHAIN           43..367
FT                   /note="Pepsin A"
FT                   /id="PRO_0000026047"
FT   DOMAIN          59..364
FT                   /note="Peptidase A1"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01103"
FT   ACT_SITE        77
FT   ACT_SITE        260
FT   CARBOHYD        113
FT                   /note="N-linked (GlcNAc...) asparagine"
FT   DISULFID        90..95
FT   DISULFID        251..255
FT   DISULFID        290..323
SQ   SEQUENCE   367 AA;  40432 MW;  0C547E7FD8F5B341 CRC64;
     SIHRVPLKKG KSLRKQLKDH GLLEDFLKKH PYNPASKYHP VLTATESYEP MTNYMDASYY
     GTISIGTPQQ DFSVIFDTGS SNLWVPSIYC KSSACSNHKR FDPSKSSTYV STNETVYIAY
     GTGSMSGILG YDTVAVSSID VQNQIFGLSE TEPGSFFYYC NFDGILGLAF PSISSSGATP
     VFDNMMSQHL VAQDLFSVYL SKDGETGSFV LFGGIDPNYT TKGIYWVPLS AETYWQITMD
     RVTVGNKYVA CFFTCQAIVD TGTSLLVMPQ GAYNRIIKDL GVSSDGEISC DDISKLPDVT
     FHINGHAFTL PASAYVLNED GSCMLGFENM GTPTELGEQW ILGDVFIREY YVIFDRANNK
     VGLSPLS