Statements related to human Insulin are given below. Which statement(s) is/are correct about genetically engineered Insulin?

(a) Pro-hormone insulin does not contain an extra stretch of C-peptide.

(b) A-peptide and B-peptide chains of insulin were produced separately in E.coli, extracted, and combined by creating a disulfide bond between them.

(c) Insulin used for treating Diabetes was extracted from cattle and Pigs.

(d) Pro-hormone Insulin needs to be processed for converting into a mature and functional hormone.

(e) Some patients develop allergic reactions to foreign insulin.

Choose the most appropriate answer from the options given below:

Concept:

• Genetic engineering is the process of manipulating the genetic makeup of an organism.
• Genetic engineering is performed using recombinant DNA technology.
• Insulin can be produced using genetic engineering for large-scale production, for treating Diabetic patients.

Explanation:

Statement a:

• Genetically engineered insulin does not contain the C peptide.

Statement b:

• A-peptide and B-peptide chains of insulin were produced separately in E.coli.
• These peptide chains are then extracted and recombined by the formation of disulfide bonds between them.

​Statement c:

• Genetically engineered insulin used for treating diabetes was not isolated from cattle and Pigs. 
• Rather it was artificially manufactured using E.coli.

​​Statement d:

• Proinsulin has to be further processed to become functional.
• Proinsulin contains another peptide chain known as ‘C’ peptide in addition to ‘A’ and ‘B’ peptides, which are required for its functionality.
• From proinsulin, the C peptide is removed at the time of maturation.
• Genetically engineered insulin does not contain the C peptide.

​Statement e:

• Insulin from an animal source, though caused some patients to develop allergies or other types of reactions to the foreign protein.

So, the correct answer is Option 3.