Biochemistry – MCQ 91 – Genetic defect of fructose 1,6 – biphosphatase

A genetic disorder renders fructose 1,6 — biphosphatase in liver less sensitive to regulation by fructose 2,6 — bi-phosphate. All of the following metabolic changes are observed in this disorder except:
A. Level of fructose 1,6—biphosphate is higher than normal
B. Level of fructose 1,6 — biphosphate is lower than normal
C. Less pyruvate is formed
D. Less ATP is generated

Correct answer : A. Level of fructose 1,6—biphosphate is higher than normal

Fructose 2,6 – biphosphate acts to decrease the activity of fructose 1,6 – biphosphatase. When the enzyme becomes less sensitive to regulation, the inhibitory effect is lost and the enzyme activity increases. The following effects are observed:
1. Level of fructose 1,6 — biphosphate decreases
2. Pyruvate is used up for glucose synthesis
3. ATP is used up for glucose synthesis