Rate-limiting Enzymes

Question 1

Glycolysis

Answer 1

Phosphofructokinase-1 (PFK-1)

- Regulated + by AMP, fructose-2,6-Bisphosphonate and (neg) by ATP and citrate

Question 2

Gluconeogenesis

Answer 2

Fructose-1,6-bisphosphatase

- Regulated pos by ATP and neg by fructose,2-6-bisphosphonate and AMP

Question 3

TCA Cycle

Answer 3

Isocitrate Dehydrogenase

- Regulated pos by ADP and neg by ATP and NADH

Question 4

Glycogen Synthesis

Answer 4

Glycogen Synthase

- Regulated pos by glucose, insulin and neg by Epi, glucagon

Question 5

Glycogenolysis

Answer 5

Glycogen Phosphorylase

- Regulated pos by AMP, Epi, glucagon, and neg by insulin, ATP

Question 6

HMP Shunt

Answer 6

Glucose-6-phosphate dehydrogenase (G6PD)

- Regulated pos by NADP+ and neg by NADPH

Question 7

De novo Pyrimidine synthesis

Answer 7

Carbamoyl phosphate synthetase II

Question 8

De novo purine synthesis

Answer 8

Glutamine-PRPP amidotransferase

Question 9

Urea Cycle

Answer 9

Carbamoyl Phosphate Synthetase I

- Regulated pos by N-acetylglutamate

Question 10

Fatty Acid Synthesis

Answer 10

Acetyl-CoA carboxylase (ACC)

- Regulated pos by insulin, citrate and neg by glucagon, palmitoyl-CoA

Question 11

Fatty Acid Oxidation

Answer 11

Carnitine acyltransferase I

- Regulated neg by Malonyl-CoA

Question 12

Ketogenesis

Answer 12

HMG-CoA Synthase

Question 13

Cholesterol Synthesis

Answer 13

HMG-CoA Reductase

- Regulated pos by insulin, thyroxine and neg by glucagon, cholesterol