Flashcards in FA's Synthesis Deck (15):
What are the 4 functions of lipids?
other (insulation, generation of heat)
How much would a man weight if TAG was changed to Gylcogen?
70kg man weight 134kg (6.75 more energy for fats)
FA synthesis occurs primarily in what organ?
Other organs also carry out process?
Also adipose tissue, kidney, brain, lactatiting mammary gland
What is the first enzyme in FA synehtesis? What RXn catalyze?
Citrate synthase First step in CAC
Shuttle out Citrate into cytoplasm
Positive and Negative Regulations of
ATP Citrate synthesis?
+: Glucose, insulin induce gene expression
Phosphorylation of enzyme
-: PUFA (Polyunsaturated Fatty Acid), leptin
What is the rate limiting step of FA synthesis?
What is used as a cofactor for this enzyme?
Conversion of acetyl CoA to malonyl CoA by Acetyl CoA Carboxylase also uses CO2 and ATP
Cofactor: Biotin (B7)
Positive and Negative Regulations for Acetyl CoA Carbozylase (ACC)?
allosteric binding + citrate ; - Palmate (long chain FA)
Phosphorylation (-)/Dephosphorylation (+)
• Insulin (+) via activation of protein phosphatase
• Epinephrine (-) via activation of protein kinase A
• Glucagon (-) via activation of protein kinase A
• AMP (-) via activation of AMP kinase (energy sensor) Induction/repression
• Gene expression up-regulated by high carb/low fat diet
What does Malonyl CoA do for degradation of FA?
Works as an inhibitor for carnitine acetyltransferase used for FA degradation so do not occur similtaneously
Fatty Acid Sythase is made up of?
2 dimers arranged head to tail with 7 enzyme activities and Acyl carrier protein
How is the Fatty Acid Synthetase regulated?
• Allosteric effect (presence of phosphorylated
sugars) – increase activity
• Induction and repression at gene level
– Insulin and glucocorticoid hormones increase
– High carb/low fat diets increase synthesis.
– High fat diets as well as starvation lowers synthesis.
– High PUFA suppresses synthesis
What did Leptin Show us?
Leptin hormone secreted by adipose tissue (in proportion) and regulated body weight by inhibiting food intake, stimulating energy expenditure
binds in hupothalamus to receptor
Where can palmate be enlogated?
What are the two carbon donators?
SER and Mitocondria
SER uses Malonyl CoA and Mitocondria Acetyl Co A
What enzyme is used as a desaturase? Where can they desaturate on the molecule?
Aceyl Co A desaturases
4, 5, 6, 9 only all other require essential FA's
What are the homones that regulate the desaturase?
Insulin induce and Polyunsaturated FA will suppress
Cholesterol induces Delta 9, suppresses others