EC - Pepsin A

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IntEnz Enzyme Nomenclature


Accepted name:
pepsin A
Other names:
elixir lactate of pepsin
lactated pepsin
lactated pepsin elixir
pepsin D
pepsin R
pepsin fortior
Systematic name:



The predominant endopeptidase in the gastric juice of vertebrates, formed from pepsinogen A by limited proteolysis. Human pepsin A occurs in five molecular forms. Pig pepsin D [1,2] is unphosphorylated pepsin A. Type example of peptidase family A1. Formerly EC

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , MEROPS , NIST 74 , UniPathway
Protein domains and families: PROSITE:PDOC00128
Structural data: CSA , EC2PDB
Gene Ontology: GO:0004190
CAS Registry Number: 9001-75-6
UniProtKB/Swiss-Prot: (22) [show] [UniProt]


  1. Lee, D. and Ryle, A.P.
    Pepsinogen D. A fourth proteolytic zymogen from pig gastric mucosa.
    Biochem. J. 104 : 735-741 (1967). [PMID: 4167464]
  2. Lee, D. and Ryle, A.P.
    Pepsin D. A minor component of commercial pepsin preparations.
    Biochem. J. 104 : 742-748 (1967). [PMID: 4860638]
  3. Foltmann, R.
    Gastric proteinases -structure, function, evolution and mechanism of action.
    Essays Biochem. 17 : 52-84 (1981). [PMID: 6795036]
  4. James, M.N.G. and Sielecki, A.R.
    Molecular structure of an aspartic proteinase zymogen, porcine pepsinogen, at 1.8 Å resolution.
    Nature 319 : 33-38 (1986). [PMID: 3941737]
  5. Fruton, J.S.
    Aspartyl proteinases.
    In: Neuberger, A. and Brocklehurst, K. (Eds.) New Comprehensive Biochemistry , Elsevier , Amsterdam , 1987 , 1-38
  6. Tang, J. and Wong, R.N.S.
    Evolution in the structure and function of aspartic proteases.
    J. Cell. Biochem. 33 : 53-63 (1987). [PMID: 3546346]
  7. Pohl, J. and Dunn, B.M.
    Secondary enzyme-substrate interactions: kinetic evidence for ionic interactions between substrate side chains and the pepsin active site.
    Biochemistry 27 : 4827-4834 (1988). [PMID: 3139029]

[EC created 1961 as EC, transferred 1972 to EC, modified 1986, modified 1989]