Fatty Acid Synthesis Flashcards Preview

Biochem > Fatty Acid Synthesis > Flashcards

Flashcards in Fatty Acid Synthesis Deck (30):
1

Primary tissues for fatty acid synthesis

Liver*, kidney, brain, lung, mammary glands, adipose

2

Where does fatty acid sythesis occur in the cell?

Cytosol

3

What are fatty acids synthesised from?

acetyl-CoA

4

What is the main source of acetyl-CoA?

Glucose

5

Major enzymes in fatty acid synthesis

Acetyl-CoA carboxylase, Fatty Acid synthase

6

From what is citrate formed?

Acetyl-CoA and OAA

7

Citrate lyase

Cleaves citrate into Acetyl-CoA and OAA. Is only found in the cytosol.

8

How is pyruvate formed from OAA in the cytosol?

Cytosolic malate DH forms malate, malic Ez forms pyruvate from malate

9

Formation of Malonyl CoA

Acetyl CoA carboxylase uses CO2 and ATP to make Acetyl CoA into Malonyl CoA

10

What activates acetyl CoA carboxylase?

Insulin (activates protein phosphatase)

11

What stimulates AMPK?

AMP, AMPK covalant (via Glucagon or Epi). Inhibits aceytl-CoA Carboxylase

12

Long-term "adative" regulation

Long high calories=increased synthesis of Acetyl CoA Carboxylase. Long low calorie=decreased synthesis of acetyl CoA carboxylase

13

What are the starting and ending units of fatty acid synthase?

acetyl-CoA starts, 2 carbons added at a time, product is palmitate

14

Acetyl transacylase

Adds acetyl group on #1 monomer

15

Malonyl transacylase

Adds malonyl group on monomer #2

16

3-ketoacyl synthase

Makes a 3-ketoacyl, causes decarboxylation, passes carbons from one monor to the other (back and forth)

17

3-ketoacyl reductase

Reduces 3 ketoacyl to 2 hydroxy using NADPH

18

Hydratase

Removes H2O to form a 2-enyol group

19

Enoyl reductase

Saturates the CC double bonem uses NADPH, leaves a saturated acyl

20

Thioesterase

Breaks off acyl group to leave palmitate

21

Acyl-CoA synthase

converts palmitate to palmitoyl-CoA to allow further reactions

22

What is a major source of NADPH?

pentose phosphate pathway

23

Where does fatty acid elongation take place?

ER

24

What are the preferred substrates and products of fatty acid elongation?

Palmitoyl-CoA is substrate. Product is stearoyl-CoA (18C)

25

Why is elongation a separate process fron synthesis?

There are different enzymes doing the same process

26

Formation of monosaturated fatty acids

in the ER. Stearoyl-CoA desaturase. Desaturation always occurs at C9. Product is oleoyl CoA* or palmitoleoyl-CoA (stearoyl is preferred).

27

Functions of polyunsaturated fatty acids

increases membrane fluidity, source of eicosanoids

28

What carbons can humans desaturate?

4,5,6, and 9. CANNOT desaturate Beyond* C9

29

What are omega fatty acids?

Fatty acids counted from the furthest C, instead of the alpha carbon

30

Why are omega 3 and 6 necessary for dietary intake?

Cannot synthesize past C9, so must be taken in via diet