Chapter 9, Problem 29P

Summary Introduction

To review:

Three essential posttranslational steps are mentioned in figure $\text{9}\text{.17}$ of the book, required to produce the sugar-regulating hormone insulin from the initial polypeptide product preproinsulin.

a. A research scientist is intent to produce human insulin in the bacterial species E. coli. Whether the genetic code permits the production of human proteins from bacterial cells? Explain with reason.

b. Describe why it is not feasible to insert the complete human insulin gene E. coli and anticipate the production of insulin.

c. Recombinant human insulin that is prepared by inserting human DNA encoding insulin into E. coli, is one the most extensively used recombinant in pharmaceutical products in the world. Recognize the part of the human insulin gene used to generate recombinant bacteria that produce human insulin.

Introduction:

Preproinsulin is the primary translational product of the Insulin gene. It is made up of $\text{110}$ amino acids. It is an inactive precursor of insulin; preproinsulin is converted to proinsulin by peptidases signals. The final stage of the process is conversion of proinsulin to an active form of insulin.

The post translational modifications include cleavage of N terminal amino acids, Chemical modification of internal amino acids, and polypeptide cleavage.