proinsuliiniksi

Proinsuliini is the precursor protein to insulin. It is synthesized in the beta cells of the pancreas. Structurally, proinsulin is a single polypeptide chain consisting of three domains: an amino-terminal B-chain, a connecting peptide known as the C-peptide, and a carboxyl-terminal A-chain. Initially, proinsulin is produced as a larger molecule, but it undergoes post-translational modification within the endoplasmic reticulum and Golgi apparatus. During this process, specific enzymes cleave the C-peptide, separating it from the insulin molecule. Insulin then consists of the A-chain and B-chain linked together by disulfide bonds. The C-peptide is released as a byproduct and is also secreted into the bloodstream. The conversion of proinsulin to mature insulin is a crucial step in the regulation of blood glucose levels. Measuring C-peptide levels can be useful in assessing pancreatic beta cell function and insulin production, particularly in individuals with diabetes. Defects in proinsulin processing can lead to the production of abnormal insulin molecules or impaired insulin secretion, potentially contributing to metabolic disorders.