Question

How is a mature, functional insulin hormone different from its prohormone form?

Answer 1

Insulin hormone :

In mammals including humans, insulin is synthesized as a prohormone known as proinsulin. It has to be processed to become a fully functional hormone.

Presence of C peptide :

Immature proinsulin has C peptide present in between the A and B peptide chains. Mature insulin does not have C peptide, instead are connected by a disulphide bridge.

Origin :

Immature proinsulin is derived from the pre-proinsulin. Mature functional insulin is derived from the prohormone called proinsulin.

Functionality:

Immature insulin is nonfunctional. Mature insulin is functional.

Pictorial representation:
Summary:

Criteria	Mature insulin	Immature proinsulin
Presence of C peptide	Made up of A and B peptides.	Made up of A, B and C peptides present.
Origin	Derived from proinsulin.	Derived from pre proinsulin
Functionality	Functional	Nonfunctional