Mutant MT-SP1 proteases with altered substrate specificity or activity

A mutein membrane type serine protease 1 (MT-SP1) protease that comprises at least one mutation in a scaffold MT-SP1 polypeptide, whereby the substrate specificity or activity of the mutein MT-SP1 polypeptide is altered compared to the scaffold MT-SP1 polypeptide, wherein:

• the scaffold MT-SP1 polypeptide comprises a sequence of amino acids that is at least 95% identical or is identical to the amino acid sequence of a wild type MT-SP1 whose sequence is set forth in SEQ ID NO:1 or SEQ ID NO:2 or is a species variant of the wild type MT-SP1 of SEQ ID NO:1, or is a catalytically active portion thereof;
• the mutein MT-SP1 comprises a mutation at a position selected from among amino acid positions 41, 146, 151, 169, 170, 172, 173, 175, 176, 177, 178, 179, 181, and 224;
• and
• the numbering is for chymotrypsin.