Preproinsulin Synthesis:

Synthesized in the endoplasmic reticulum (ER).

Proinsulin Formation:

Signal peptide removal creates proinsulin with A, B chains, and C peptide.

Transport to Golgi:

Proinsulin transported to the Golgi apparatus.

Proteolytic Cleavage:

Endopeptidases in secretory vesicles cleave C peptide from proinsulin.

Insulin and C Peptide:

Cleavage yields mature insulin and C peptide.

Storage and Release:

Stored in vesicles until stimuli trigger release.

Biological Activity:

Released insulin enters bloodstream, exerting biological effects.

C Peptide Function:

C peptide, though cleaved, has physiological functions.

Review: Intracellular proteolysis (The Living Cell) UNFINISHED