Microbial regulation

Question 1

What is the difference between enzyme repression and enzyme induction? Give one example of each.

Answer 1

Enzyme repression
• The final product (corepressor) of a biosynthetic
pathway represses the enzymes of the process
• Often anabolic enzymes (e.g. arginine-operon)

Enzyme induction
• An enzyme (inducers) is made only when its substrate is present
• Often catabolic enzymes (e.g. the lactose-operon)
The enzymes bind to specific DNA-binding proteins, which in turn affect gene transcription