Regulators/Regulatory Mechanisms

Question 1

Acetyl-CoA Carboxylase (ACC)

Answer 1

biotin requiring enzyme
allosteric activator = citrate
allosteric inhibitor = long chain fatty acyl-CoA
DePhosphorylation = high I/G = Active
Phosphorylation by AMP-Kinase (AMPK) = inactive
Sterol-dependent regulation via SRE and SREBP
-Insulin signal leads to the proteolytic cleavge of SREBP from ER (release of SREBP) resulting in the ACC gene expression and lipogenesis
Glucagon and dietary PUFAs prevent release of SREBP resulting in decrease in ACC and lipogen

Question 2

citrate

Answer 2

+ ACC (polymerization)
+ ATP-Citrate Lyase (feed forward)
- PFK-1
- citrate snythase

Question 3

Fructose-2,6-bisPhosphate and AMP

Answer 3

+ PFK1

- FBPase1

Question 4

Calcium

Answer 4

+ PDH Phosphatase (which activates PDHC via dephosphorylation)
+ Isocitrate dehydrogenase
+ KGDHC
+ glycogenolysis

Question 5

Acetyl-CoA

Answer 5

+ pyruvate carboxylase (TCA Priming/ gluconeogenesis)
+ PDH Kinase (which inhibits PDHC via phosphorylation)
+ mitochondrial HMG-CoA synthase (ketogenesis)

Question 6

F-1,6-BP

Answer 6

+ pyruvate kinase (feed forward)

Question 7

Malonyl CoA

Answer 7

• CPT-1 (fatty acid oxidation

Question 8

cholic acid

Answer 8

• cholesterol 7-a-hydroxylase

Question 9

NADH

Answer 9

• Isocitrate Dehydrogenase
• KGDHC
• PDHC
  + PDH Kinase (Which phosphorylates PDHC and inactivates PDHC)

Question 10

AMPK

Answer 10

phosphorylates ACC (inhibits lipogenesis)
AMPK will elevate F-2,6-BP production during circulatory system collapse

Question 11

ATP

Answer 11

+ PDH Kinase (which phosphorylates and inactivates PDHC)
- Isocitrate dehydrogenase
+ FBPase1

Question 12

PUFAs

Answer 12

decrease release of SREBP

decrease gene expression of ACC and HMG-CoA reductase

Question 13

High I/G/Fed, & what is the covalent modification status

Answer 13

DEPHOSPHORYLATION
+ Pyruvate Kinase (glycolysis)
+ Acetyl-CoA carboxylase (de nova FA snyth)
+ HMG-CoA Reductase (de novo cholesterol snth)
+ Glycogen Synthase A (glycogenesis)
+ PDHC
+ PFK-2 (making more F-2,6-BP which activates PFK1) (Glycolysis)

Question 14

Fast (Low I/G / high epinephrine)

Answer 14

Phosphorylation
+hormone-sensitive lipase
+glycogen phosphorylase a (glycogenolysis)
+ FBP-2 (which decreases F-2,6-BP, which would otherwise allosterically activate PFK1)

Question 15

Oversupply of cholesterol

Answer 15

• Synthesis of LDL receptors
• HMG-Coa reductase (ie synthesis cholesterol) (regulation via SREBP)
  + ACAT (which takes cholesterol and makes cholesterol esters for storage
  + cholesterol 7a-hydroxylase

Question 16

AMP

Answer 16

+ PFK1

- FBPase1