Fatty Acid Synthesis Flashcards
What is the main organ of fatty acid synthesis?
Liver
What is the cellular location of fatty acid synthesis?
Cytosol
Function of the malate citrate antiporter
Malate citrate antiporter moves acetyl CoA from mitochondria to cytoplasm
Describe the function of the malic enzyme and name the coenzyme needed
Malate becomes pyruvate with coenzyme NADPH
What is the reaction for Stage 1 of fatty acid synthesis?
Acetyl CoA + CO2 -> Malonyl CoA
What is the name of the enzyme needed for Stage 1 of fatty acid synthesis? What coenzymes?
Acetyl CoA carboxylase with biotin and ATP
What upregulates acetyl CoA carboxylase?
High carb/ low fat diet, insulin, citrate
What down regulates acetyl CoA carboxylase?
High fat/ low carb diet, glucagon, epinephrine
What is the overall reaction for Stage 2 of fatty acid synthesis?
8 Acetyl CoA + 7 malonyl CoA + 14 NADPH -> palmitate + 7CO2 + 7H2O
What enzyme is used for Stage 2 of fatty acid synthesis?
Fatty acid synthase
What is the end product of Stage 2 of fatty acid synthesis?
Palmitate, CO2, H2O
malate citrate antiporter
Citrate becomes OAA + acetyl CoA using what enzyme?
ATP citrate lyase
malate citrate antiporter
OAA becomes malate using what enzyme and coenzyme?
Malate dehydrogenase with NADH
malate citrate antiporter
Malate becomes pyruvate using what enzyme and coenzyme?
Malic enzyme with NADPH
malate citrate antiporter
Through a chain of reactions, citrate will become pyruvate which enters…
the mitochondria
Describe the malate shuttle
Acetyl CoA from the mitochondria enters the cytoplasm via the malate-citrate antiporter
Describe fatty acid synthase
7 distinct enzyme activities, dimer, arranged head to tail
What upregulates fatty acid synthase?
High carb/ low fat diet
What down regulates/ inhibits fatty acid synthase?
High levels of free fatty acids
What is the name of the enzyme that converts palmitate to stearate?
Fatty acid elongase (with NADPH)
What molecule is added in fatty acid elongation and synthesis of other fatty acids?
Malonyl CoA
What coenzymes are needed for fatty acid elongation and synthesis of other fatty acids?
NADPH
What is the process for creating short chain fatty acids?
Reverse of beta oxidation of fats in the mitochondria
Where are very long chain fatty acids synthesized?
Brain
What molecule is added for very long chain fatty acid synthesis?
Elongation of stearoyl CoA
What are very long chain fatty acids used for?
Synthesis of sphingolipids during myelination
Synthesis of TAGs in the liver consists of ___ being converted to ___ using enzyme ___
glycerol being converted to glycerol 3P using enzyme glycerol kinase
Fatty acids are stored as ___
Triacylglycerol
Synthesis of TAGs in adipose consists of ___ from ___ being converted to ___
DHAP from glycolysis being converted to glycerol 3P
In TAG synthesis, glycerol 3P, using 2 acyl CoA, becomes ___, then ___
phosphatidic acid, then diacylglycerol
In TAG synthesis, diacylglycerol becomes triacylglycerol using what enzyme?
Acyl CoA
How are TAGs stored in the liver?
How are they stored in adipose tissue?
Blood VLDL in liver
Adipose stores in fat cells
What are three factors that regulate total body fat?
- Number and size of adipocytes
- Genetically linked factors- dopamine receptors
- Leptin
Where is leptin made? What is its target?
Produced by white adipose tissue, targeting the hypothalamus
What are three environmental factors that increase food intake and lead to increased body fat?
- Eating a wide variety of food
- Eating with more people
- Availability of energy dense foods
