Rate Limiting Enzymes

Question 1

Cholesterol Synthesis

Answer 1

HMG-CoA Reductase

+: Insulin, Thyroxine
-: Glucagon, Cholesterol

Question 2

De Novo Purine Synthesis

Answer 2

Glutamine-Phosphoribosylpyrophosphate (PRPP) amidotransferase

-: AMP, IMP, GMP

Blocked by 6MP

Question 3

De Novo Pyrimidine Synthesis

Answer 3

Carbamoyl Phopshate Synthetase II (Cytosol)

Question 4

Fatty Acid Oxidation

Answer 4

Carnitine Acyltransferase I

-: Maloynl-CoA

Carnage Fatty acids

Question 5

Fatty Acid Synthesis

Answer 5

Acetyl-CoA Carboxylase (ACC)

+: Insulin, Citrate
-: Glucagon, Palmityol-CoA

Question 6

Gluconeogenesis

Answer 6

Fructose 1,6 BIsphosphatase

+: ATP and Acetyl-CoA
-: AMP and F26BP

Question 7

Glycogenesis

Answer 7

Glycogen Synthase

+: G6P, Insulin, Cortisol
-: Epinephrine, Glucagon

Question 8

Glycogenolysis

Answer 8

Glycogen Phosphorylase

+: Epinephrine, Glucagon, AMP
-:G6P, Insulin, ATP

Question 9

Glycolysis

Answer 9

Phosphofructokinase-1 (PKF-1)

Regulators: Positive: AMP and F26BP
Negative: ATP and Citrate

Question 10

HMP Shunt

Answer 10

Glucose 6 Phosphate Dehydrogenase

+: NADP+
-: NADPH

Question 11

Ketogenesis

Answer 11

HMG-CoA Synthase

Question 12

TCA Cycle

Answer 12

Isocitrate Dehydrogenase

+: ADP
-: ATP, NADH

Question 13

Urea Cycle

Answer 13

Carbamoyl Phosphate Synthetase I (Mitochondria)

+: N-Acetylglutamate

Question 14

Heme Synthesis

Answer 14

delta aminolevulinic acid synthase

Defected in Sideroblastic anemia

• glucose and heme