The Colostrum trypsin inhibitor (CTI) gene is expressed in the Cape fur seal mammary gland.
CTI encodes a small glycosylated protein with a single Kunitz/bovine pancreatic trypsin inhibitor (BPTI) domain.
Homology modelling suggests that CTI inhibits trypsin in a canonical mechanism.
CTI may enhance pup survival by preventing the proteolysis of immunoglobulins.