Novel adamts-13 mutant

An ADAMTS-13 (a disintegrin-like domain, and metalloprotease, with an isolated human thrombospondin type 1 motif, member 13) mutant, comprising a substitution of the following positions in the isolated human ADAMTS-13 with a different amino acid:

• aspartic acid at position 287, aspartic acid at position 298, glutamic acid at position 309, arginine at position 312, lysine at position 318, glutamic acid at position 327, aspartic acid at position 340, glutamic acid at position 363, lysine at position 364, lysine at position 368, arginine at position 370, arginine at position 372, arginine at position 386, arginine at position 452, arginine at position 459, glutamic acid at position 492, lysine at position 497, aspartic acid at position 500, aspartic acid at position 504, arginine at position 514, glutamic acid at position 515, aspartic acid at position 516, arginine at position 535, aspartic acid at position 537, arginine at position 544, aspartic acid at position 551, asparagine at position 552, arginine at position 558, lysine at position 559, arginine at position 566, arginine at position 568, glutamic acid at position 569, asparagine at position 579, lysine at position 608, asparagine at position 614, arginine at position 625, arginine at position 629, glutamic acid at position 634, aspartic acid at position 635, arginine at position 636, arginine at position 639, arginine at position 644, glutamic acid at position 651, arginine at position 659, glutamic acid at position 663, glutamic acid at position 664, asparagine at position 667, arginine at position 670, or arginine at position 683 in the amino acid sequence encoded by the nucleotide sequence of SEQ ID NO:1.