PAI-1 has mutation(s) inserted to increase the half-life of the protein. The Human PAI-1 is a collection of four mutations: K154T, Q139L, M354I and H150H. These mutations offer great stability while locking PAI-1 into its active conformation, making it ideal for in vivo studies. The Mouse and Rat PAI-1 have a single mutation, I91L, to create an enhanced half-life as compared to the wild type form.
PI05 PAI-1 (Human),  Stable Mutant
PI18 PAI-1 (Mouse),