- A novel form of gastric inhibitory polypeptide (GIP) isolated from bovine intestine using a radioreceptor assay. Fragmentation with staphylococcal protease results in GIP1-3 and GIP4-42, fragmentation with enterokinase in GIP1-16 and GIP17-42. Carlquist, M., Maletti, M., Jörnvall, H., Mutt, V. Eur. J. Biochem. (1984)