Identification of a new serine protease, signed at the Graduate Institute of Oncology, University of Oviedo. The authors cloned a human DNA encoding this new enzyme, named polisher's 2 the second identified human enzyme with several tandem serine protease domains in its amino acid sequence. The article describes its complex organization in domains, also present in the sequences of the two polisher's rat and mouse, and similar to the polisher's 1. The first of three serine protease domain contains all the characteristics of these enzymes, while the second and third lack a key residue, so that it predicts them to be catalytically inactive.

 
The authors make a series of enzyme assays with peptide substrates commonly

used to assess serine proteases, and the results show that both the polisher's 2 completes its first serine protease domain hydrolyzed these peptides, but with the particularity that the activity of the isolated domain is greater than that of the whole protein, indicating that the two catalytic domains inactive polisher's 2 can modulate the activity of the first domain. As for human tissues which express this enzyme, the authors identified by its presence in Northern blot fetal kidney, skeletal muscle, liver, placenta, prostate and heart, as well as tumor cell lines derived from Aden carcinomas of the lung and colon. The signatories conclude that this new polyprotein is a secreted enzyme whose three protease domains remain as integral parts of a single polypeptide chain.

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