Parent Class:

EC-Numbers → 3 -- Hydrolases → 3.4 -- Acting on peptide bonds (peptide hydrolases) → 3.4.21 -- Serine endopeptidases

Unification Links: BRENDA:3.4.21.106, ENZYME:3.4.21.106, IUBMB-ExplorEnz:3.4.21.106

Reaction:
protein + H₂O → 2 peptide + 2 H⁺

Summary:
This type-II membrane-associated serine peptidase has been implicated in cell growth and development. The enzyme has been shown to activate blood coagulation factor VII by cleavage of the 152-Arg-|-Ile-153 peptide bound in BHK cells, thus indicating a possible role in the initiation of blood coagulation.

The enzyme cleaves after basic amino-acid residues, with Arg strongly preferred to Lys. There is no cleavage after aromatic or aliphatic residues. The occupancy of the S2 site is an absolute requirement for catalysis and a basic residue at that site is preferred to an aliphatic residue. The nature of the residue at S3 also affects hydrolysis, with Gln being much more favorable than Ala. Belongs to peptidase family S1A.

Citations: [TorresRosado93, Kazama95, Zhukov97]

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References

Kazama95: Kazama Y, Hamamoto T, Foster DC, Kisiel W (1995). "Hepsin, a putative membrane-associated serine protease, activates human factor VII and initiates a pathway of blood coagulation on the cell surface leading to thrombin formation." J Biol Chem 270(1);66-72. PMID: 7814421

TorresRosado93: Torres-Rosado A, O'Shea KS, Tsuji A, Chou SH, Kurachi K (1993). "Hepsin, a putative cell-surface serine protease, is required for mammalian cell growth." Proc Natl Acad Sci U S A 90(15);7181-5. PMID: 8346233

Zhukov97: Zhukov A, Hellman U, Ingelman-Sundberg M (1997). "Purification and characterization of hepsin from rat liver microsomes." Biochim Biophys Acta 1337(1);85-95. PMID: 9003440

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 46(D1):D633-D639 2018
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