A high molecular weight form of pancreatic polypeptide was present in USP insulin and is absent in a more recent insulin preparation.
The concentrations and molecular forms of pancreatic polypeptide (PP) and glucagon were determined in USP XX and single-peak insulin preparations. In USP insulin the concentration of PP was 7 ng mg-1 insulin; on gel chromatography the PP immunoreactivity fractionated into two peaks of about equal size. One of the PP peaks was in the region of 4200 dalton PP, and the other PP peak eluted earlier in the region of a 7000-10,000 dalton peptide. The concentration of PP in single-peak insulin was 0.8 ng mg-1 insulin; the immunoreactivity eluted in a single peak in the region of [125I]PP. The concentration of glucagon in each preparation was 55 ng mg-1 insulin. On gel chromatography the immunoreactive glucagon in each insulin preparation eluted in the region of [125I]glucagon.
D005934:Glucagon / Q000032:analysis; D007328:Insulin / Q000032:analysis*; D008970:Molecular Weight; D010191:Pancreatic Polypeptide / Q000032:analysis* / Q000276:immunology
D007328:Insulin; D010191:Pancreatic Polypeptide; D005934:Glucagon