EC 3.4.23.1

Reaction: Preferential cleavage: hydrophobic, preferably aromatic, residues in P1 and P1' positions. Cleaves Phe¹Val, Gln⁴His, Glu¹³Ala, Ala¹⁴Leu, Leu¹⁵Tyr, Tyr¹⁶Leu, Gly²³Phe, Phe²⁴Phe and Phe²⁵Tyr bonds in the B chain of insulin

Other names: pepsin; lactated pepsin; pepsin fortior; fundus-pepsin; elixir lactate of pepsin; P I; lactated pepsin elixir; P II; pepsin R; pepsin D

Comments: 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 3.4.4.1

Links to other databases: BRENDA, EXPASY, KEGG, GTD, MEROPS, Metacyc, PDB, CAS registry number: 9001-75-6

References:

1. Lee, D. and Ryle, A.P. Pepsinogen D. A fourth proteolytic zymogen from pig gastric mucosa. Biochem. J. 104 (1967) 735-741. [PMID: 4167464]

2. Lee, D. and Ryle, A.P. Pepsin D. A minor component of commercial pepsin preparations. Biochem. J. 104 (1967) 742-748. [PMID: 4860638]

3. Foltmann, R. Gastric proteinases -structure, function, evolution and mechanism of action. Essays Biochem. 17 (1981) 52-84. [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 (1986) 33-38. [PMID: 3941737]

5. Fruton, J.S. Aspartyl proteinases. In New Comprehensive Biochemistry Vol. 16, Hydrolytic Enzymes (Neuberger, A. and Brocklehurst, K., eds), pp. 1-38 (1987) Elsevier, Amsterdam

6. Tang, J. and Wong, R.N.S. Evolution in the structure and function of aspartic proteases. J. Cell. Biochem. 33 (1987) 53-63. [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 (1988) 4827-4834. [PMID: 3139029]