proinsulin

Proinsulin is the prohormone precursor to insulin, produced in the beta cells of the pancreatic islets. It consists of a single-chain polypeptide that, after synthesis, is packaged into secretory granules and processed by specific enzymes (prohormone convertases PC1/3 and PC2, and carboxypeptidase E) to yield insulin and C-peptide. Only 1–3% of circulating proinsulin remains intact; however, due to its longer half-life compared to insulin, it can account for 5–30% of circulating insulin-like molecules. Proinsulin has some affinity for the insulin receptor but only about 5–10% of the metabolic activity of mature insulin. Elevated levels may be seen in conditions such as type 2 diabetes or in patients with insulinomas (islet cell tumors). Recombinant forms have been developed for research purposes[1][2][3][4].

Other names

proinsulin humanproinsulin biosynthetic humanrecombinant human proinsulin