This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Glycolysis, Subject name: Biochemistry
PFK-1 is inhibited by: 
Select and explain. 
A. Insulin, B. Citrate, C. Glucose-6-phosphate, D. AMP
B: Citrate
Answer: B: Citrate 
Explanation: PFK-1 (Phosphofructokinase-1) is the rate limiting enzyme of Glycolysis. Allosteric activators AMP ADP K+ Phosphate Fructose 2,6-bisphosphate Allosteric inhibitors ATP Citrate Ca ++ Mg ++ Low pH