Question

During the processing of the prohormone ‘proinsulin’ into the mature ‘insulin’.
A. C-peptide is added to proinsulin
B. C-peptide is removed from proinsulin
C. B-peptide is added to proinsulin
D. B-peptide is removed from proinsulin

Answer 1

Hint: Proinsulin is a solitary polypeptide chain made out of the B and A subunits of insulin. It is changed over to insulin during the development of secretory vesicles by the activity of two proteases and transformation is hindered by ionophores that upset intracellular H+ inclinations.

Complete answer:
C-peptide is taken out in the Golgi apparatus from proinsulin bringing about the development of the mature insulin particle with both alpha and beta chains bound together by disulfide bonds. Both insulin and C-peptide are taken care of in secretory vesicles and conveyed in an equimolar endless supply of beta cells by glucose and distinctive secretagogues.
The most significant signs for estimation of C-peptide levels incorporate the differential determination of fasting hypoglycemia with hyperinsulinemia and as a proportion of insulin secretory hold. Once emitted, both insulin and C-peptide are steered through the liver. In the liver, insulin ties to its receptors and starts glucose take-up represses gluconeogenesis, glycogenolysis, and ketogenesis, and is corrupted inside 5 to 10 minutes.

Hence, the correct answer is option (C).

Additional information:
C-peptide cannot be added to proinsulin because it has restricted debasement in the liver and is corrupted by the kidneys. Consequently, the half-existence of C-peptide is around 30 to 35 minutes.
B-type natriuretic peptide (BNP) is a heart biomarker that has become progressively valuable in various clinical settings. These peptides are basically answerable for keeping up salt and water homeostasis, yet they additionally have vasodilatory properties.

Note: Both C-Peptide and mature insulin are naturally dynamic. Cell segments and proteins in this picture are not to scale. Proinsulin is the prohormone progenitor to the insulin made in the beta cells of the islets of Langerhans, specific locations of the pancreas. In people, proinsulin is encoded by the INS quality. Thus, C-peptide is taken out from proinsulin during the cycle of 'proinsulin' into the mature 'insulin'.