Flashcards in Fatty Acid Synthesis Deck (15):
Where does FA synthesis occur?
Cytosol of mainly the liver, but also in adipose, brain, kidneys, lactating mammary glands.
Function of citrate lyase:
Citrate --> ACoA in cytosol
Regulation of citrate lyase:
+ glucose, insulin
- PUFAs, leptin
Acetyl CoA carboxylase
ACC. Catalyzes ACoA --> MCoA
Rate limiting enzyme
Malonyl CoA inhibits:
CPT 1 (aka carnitine acyltransferase), which acts in beta oxidation.
Composed of 2 dimers (head to tail orientation).
7 unique enzyme activities and acyl carrier protein (ACP).
Overall reaction for palmitate synthesis
1 ACoA + 7 MCoA + 14 NADPH + 14 H+ ------>
1 Palmitate +14 NADP+ + 8 CoA + 6 H2O
Reactions catalyzed by FAS
Con, Red, Deh, Red
Points of regulation in FA synthesis (3)
1. citrate lyase
Regulation of citrase lyase
Gene expression induced by glc/insulin, but counteracted by PUFAs and leptin.
Regulation of ACC
Inactive in dimer form (active polymer)
Allosterically reg by + citrate and - PUFAs
Regulation of FAS
Allosteric affect (presence of phosphorylated sugars) increases affect.
Other common sense regulators.
Elongation of FAs past palmitate
Done in SER and mito.
Lengthened at 2Cs at a time.
SER uses MCoA
Mito uses ACoA
Which enzyme catalyzes desaturation of FAs?
Acyl CoA desaturases, and use NADPH or NADH and O2.
FA w/ double bond beyond C9 and C10 cannot be synthesized in humans (ex: omega 3, omega 6)