Insulysin was identified nearly a century ago as an enzyme responsible for the degradation of insulin in cells, although the precise interactions between insulin and insulysin remain elusive. Human insulysin was cloned in 1988, and shown to be a 118 kDa protein that exists primarily as a homodimer, and perhaps also complexed with other molecules. The sequence is well conserved between humans, rats and mice, and the antibody recognizes these species. Insulysin is a metalloproteinase of the