题名：C-Peptide: A Molecule Balancing Insulin States in Secretion and Diabetes-associated Depository Conditions.
作者：LANDREH M; JOHANSSON J; JORNVALL H;
来源：Horm Metab Res. 2013 Oct;45(11):769-73. doi: 10.1055/s-0033-1347208. Epub 2013 [ IF= 0.00 ] ]
摘要：Gradually, the C-peptide part of proinsulin has evolved from being viewed upon as
a side product of insulin synthesis and secretion to being considered as a
bioactive peptide with endocrine functions. Independent of these, its biophysical
properties and peptide interactions point to still further roles of C-peptide, in
particular regarding possible links to diabetes-related protein aggregations.
Insulin, which can deposit at the injection sites in the treatment of diabetes,
and islet amyloid polypeptide (IAPP), which can form amyloid fibrils in the
islets of Langerhans in diabetes type 2, are kept nonaggregated by charge-based
interactions with C-peptide at defined stoichiometries. It is possible that the
conformational stabilization of insulin and IAPP by C-peptide may also
counterbalance their aggregational tendencies at the high peptide concentrations
in the pancreatic beta-cell secretory granules. The concentration imbalances of
C-peptide, insulin, and IAPP from the hyperpeptidism early in T2DM patients and
the insulin-only injections in T1DM patients may distort equilibria of these
peptide interactions and promote protein aggregation. Additionally, the
chaperone-like actions of C-peptide may increase bioavailability of insulin
supplements given to T1DM patients and prevent the formation of insulin deposits.
Similarly, peptide interactions may influence depository tendencies in additional
peptide systems. In short, biophysical studies are relevant to establish all
roles of peptide imbalances in T1DM and T2DM and associated depository diseases.