Fatty Acid Synthesis Flashcards Preview

MCM Exam 1 > Fatty Acid Synthesis > Flashcards

Flashcards in Fatty Acid Synthesis Deck (15):
1

Where does FA synthesis occur?

Cytosol of mainly the liver, but also in adipose, brain, kidneys, lactating mammary glands.

2

Function of citrate lyase:

Citrate --> ACoA in cytosol

3

Regulation of citrate lyase:

+ glucose, insulin
- PUFAs, leptin

4

Acetyl CoA carboxylase

ACC. Catalyzes ACoA --> MCoA
Rate limiting enzyme
Biotin cofactor

5

Malonyl CoA inhibits:

CPT 1 (aka carnitine acyltransferase), which acts in beta oxidation.

6

FAS structure

Composed of 2 dimers (head to tail orientation).
7 unique enzyme activities and acyl carrier protein (ACP).

7

Overall reaction for palmitate synthesis

1 ACoA + 7 MCoA + 14 NADPH + 14 H+ ------>
1 Palmitate +14 NADP+ + 8 CoA + 6 H2O

8

Reactions catalyzed by FAS

Con, Red, Deh, Red

9

Points of regulation in FA synthesis (3)

1. citrate lyase
2. ACC
3. FAS

10

Regulation of citrase lyase

+ phosphorylation
Gene expression induced by glc/insulin, but counteracted by PUFAs and leptin.

11

Regulation of ACC

RLS!
Inactive in dimer form (active polymer)
Allosterically reg by + citrate and - PUFAs
+ DEphosphorylation

12

Regulation of FAS

Allosteric affect (presence of phosphorylated sugars) increases affect.
Other common sense regulators.

13

Elongation of FAs past palmitate

Done in SER and mito.
Lengthened at 2Cs at a time.
SER uses MCoA
Mito uses ACoA

14

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)

15

Regulation of desaturases

Induced by insulin
Supressed by dietary PUFAs