Identification of Enterostatin and the Relation between Lipase and Colipase in Various Species

Enterostatin, the N-terminal activation peptide of pancreatic procolipase, has been identified in three different forms in rat: VPDPR (Val-Pro-Asp-Pro-Arg), APGPR (Ala-Pro-Gly-Pro-Arg) and VPGPR (Val-Pro-Gly-Pro-Arg). We investigated the possibility for a species to have several isoforms of enterostatin. Pancreas was purified from four different species (rat, mouse, cat and pig) and the enterostatin sequences were identified. At the same time, the activities of pancreatic lipase and colipase were measured. In rat and mouse pancreas APGPR was the only form of enterostatin identified. The colipase activity was 188 ± 25 U/mg protein in rat and 189 ± 16 U/mg in mouse and the lipase activity 354 ± 33 U/mg and 292 ± 19 U/mg respectively. Rat and mouse had a colipase/lipase ratio close to 0.5. In pancreas from cat and pig we only detected the form VPDPR (Val-Pro-Asp-Pro-Arg). We found the colipase activity in cat to be 493 ± 92 U/mg, while the lipase activity was three times lower, 167 ± 18 U/mg. Pig pancreas concentrations of colipase was 110 ± 8 U/mg and of lipase 38 ± 5 U/mg. In both cat and pig the colipase/lipase ratio was close to 3. This suggests that colipase might have an additional role than to restore the activity of lipase. Our hypothesis is that an overproduction of colipase and hence also enterostatin is involved in the regulation of fat metabolism.