Question

Researchers can manipulate the genes of a mouse so that a single gene in a single tissue either produces an inactive protein (a knockout mouse) or produces a protein that is always (constitutively) active.
What effects on metabolism would you predict for mice with the following genetic changes?
Knockout of the FBPase-2 domain of PFK-2/FBPase-2 in the liver:

Effect on glucose metabolism:
Effect on glucose levels:

Answer 1

Answer:

Glucose metabolism is impeded as the conversion of fructose-6-phosphate to fructose-2,6-bisphosphate in glycolysis is impossible after a knockout in mice.

On glucose levels, glucose levels rise as the feedback mechanism set in place to control the metabolism of glucose to ATP is absent.

Explanation:

GLUCOSE METABOLISM

PFK-2/FBPase-2 is an enzyme involved in regulating glycolysis and gluconeogenesis. It is found abundantly in organs such as the liver and heart.

It is a rate limiting enzyme critical in the catabolism of glucose which produces energy in the body.

Phosphofructokinase-2 (PFK2) catalyzes the conversion of fructose-6-phosphate to fructose-2,6-bisphosphate. PFK-2 is regulated by glucagon in the liver, epinephrine in muscle and by insulin, glucagon and epinephrine being hormones.

A knockout in mice, will conversely lead to an increased level of fructose-6-phosphate in glycolysis and with a lack of the rate limiting enzyme, glucose levels rise, leading to a consequential rise in glucose levels.

The rate limiting enzyme functions in the body's natural feedback mechanism to regulate the production of energy as well as the release of glucose for the production of energy.