Question

A) List, in order, the three enzymes that catalyze the highly regulated steps in glycolysis. (Don't just enter 1, 2, 3 for reaction numbers - give the reaction number based on the 10 steps of glycolysis.) Reaction # Enzyme Reaction # Enzyme Reaction # Enzyme B) For each of these reactions, name ONE allosteric regulator of the enzyme and whether that regulator inhibits or activates the enzyme. Reaction # allosteric regulator Inhibitor or activator? Reaction # allosteric regulator Inhibitor or activator? Reaction # allosteric regulator Inhibitor or activator? C) For each of these reactions, name the key enzyme that bypasses that step during gluconeogenesis. Glycolysis Reaction # Gluconeogenesis enzyme Glycolysis Reaction # Gluconeogenesis enzyme Glycolysis Reaction # Gluconeogenesis enzyme

Answer 1

Regulatory enzymes in Glycolysis:
1. Hexokinase:
Reaction number = 1
Allosteric inhibitor = Glucose-6-phosphate

2. Phosphofructokinase-I:
Reaction number = 3
Allosteric inhibitors = ATP, Citrate, and H+ ions
Allosteric activators = ADP, AMP, and fructose-2, 6-bisphosphate

3. Pyruvate kinase:
Reaction number = 10
Allosteric inhibitors = ATP
Allosteric activators = Fructose-1, 6-bisphosphate

In gluconeogenesis,
Hexokinase reaction is bypassed by Glucose-6-phosphatase
Phosphofructokinase reaction is bypassed by Fructose-1, 6-bisphosphatase
Pyruvate kinase reaction is bypassed by Pyruvate carboxylase and PEP carboxykinase