insulin processing

Definition

Target type: biologicalprocess

The formation of mature insulin by proteolysis of the precursor preproinsulin. The signal sequence is first cleaved from preproinsulin to form proinsulin; proinsulin is then cleaved to release the C peptide, leaving the A and B chains of mature insulin linked by disulfide bridges. [ISBN:0198506732]

Insulin, a crucial hormone regulating blood glucose levels, undergoes a complex processing journey within pancreatic beta cells. Its synthesis begins with the translation of preproinsulin mRNA, generating a precursor polypeptide containing a signal peptide, B chain, C peptide, and A chain. This preproinsulin is then translocated into the endoplasmic reticulum (ER), where the signal peptide is cleaved, resulting in proinsulin. Proinsulin undergoes folding and disulfide bond formation within the ER, ensuring its proper structure. Subsequently, proinsulin is transported to the Golgi apparatus, where it encounters prohormone convertases, specifically PC1/3 and PC2. These enzymes cleave proinsulin at specific sites, removing the C peptide and generating mature insulin composed of the A and B chains linked by disulfide bonds. This mature insulin is packaged into secretory granules within the Golgi, ready for release upon stimulation. The C peptide, a byproduct of the cleavage process, is also stored within the granules and co-released with insulin. When blood glucose levels rise, the pancreatic beta cells release insulin via exocytosis, triggering glucose uptake and utilization by cells, thus maintaining metabolic homeostasis.'
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Proteins (2)

Compounds (2)