ID   PEPA_URSTH              Reviewed;          60 AA.
AC   P13636;
DT   01-JAN-1990, integrated into UniProtKB/Swiss-Prot.
DT   01-JAN-1990, sequence version 1.
DT   03-AUG-2022, entry version 94.
DE   RecName: Full=Pepsin A;
DE            EC=3.4.23.1;
DE   Flags: Precursor; Fragment;
GN   Name=PGA;
OS   Ursus thibetanus (Asiatic black bear) (Selenarctos thibetanus).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC   Eutheria; Laurasiatheria; Carnivora; Caniformia; Ursidae; Ursus.
OX   NCBI_TaxID=9642;
RN   [1]
RP   PROTEIN SEQUENCE.
RX   PubMed=6418734;
RA   Kageyama T., Moriyama A., Takahashi K.;
RT   "Purification and characterization of pepsinogens and pepsins from Asiatic
RT   black bear, and amino acid sequence determination of the NH2-terminal 60
RT   residues of the major pepsinogen.";
RL   J. Biochem. 94:1557-1567(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   -!- SUBCELLULAR LOCATION: Secreted.
CC   -!- SIMILARITY: Belongs to the peptidase A1 family. {ECO:0000305}.
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DR   PIR; A28859; A28859.
DR   AlphaFoldDB; P13636; -.
DR   SMR; P13636; -.
DR   MEROPS; A01.078; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0004190; F:aspartic-type endopeptidase activity; IEA:UniProtKB-KW.
DR   GO; GO:0007586; P:digestion; IEA:UniProtKB-KW.
DR   GO; GO:0006508; P:proteolysis; IEA:UniProtKB-KW.
DR   InterPro; IPR001461; Aspartic_peptidase_A1.
DR   InterPro; IPR012848; Aspartic_peptidase_N.
DR   PANTHER; PTHR47966; PTHR47966; 1.
DR   Pfam; PF07966; A1_Propeptide; 1.
PE   1: Evidence at protein level;
KW   Aspartyl protease; Digestion; Direct protein sequencing; Hydrolase;
KW   Protease; Secreted; Zymogen.
FT   PROPEP          1..45
FT                   /note="Activation peptide"
FT                   /id="PRO_0000026044"
FT   CHAIN           46..>60
FT                   /note="Pepsin A"
FT                   /id="PRO_0000026045"
FT   NON_TER         60
SQ   SEQUENCE   60 AA;  7052 MW;  C6BFDC560D4EEE1A CRC64;
     FIIKVPLVKK KSLRKNLKEH GLLKDFLKKH SPNPASKYFP QEAAVMATQP LENYMDMEYF