Question

E.coli is not a perfect host due to __________

(a) Non-proteolytic degradation

(b) Proteolytic degradation

(c) Retained intercellularly

(d) Production at medium levels

This question was posed to me in final exam.

This is a very interesting question from Guidelines for Choosing Host-Vector Systems in division Utilizing Genetically Engineered Organisms & Medical Applications of Bioprocess Engineering of Bioprocess Engineering

Answer 1

Correct choice is (b) Proteolytic degradation

The explanation: E. coli is not a perfect host. The major problems result from the fact E. coli does not normally secrete proteins. When proteins are retained intracellularly and produced at high levels, the amount of soluble active protein present is usually limited due to either proteolytic degradation or insolubilization into inclusion bodies.