Q) In what compartment does the de novo fatty acid synthesis occurs?
a) Mitochondria
b) Perioxosome
c) Endoplasmic reticulum
d) Cytosol
Explanation
Fatty acid biosynthesis takes place in the cytosol
Intermediates covalently linked to an acyl carrier protein
The acetyl CoA is activated to malonyl CoA
Four steps repeating cycle are condensation, reduction, dehydration, and reduction. One cycle leads to extension by 2-carbons
Comparison of Fatty acid synthesis and oxidation
Characteristics
|
Synthesis
|
Degradation
|
Location
|
Cytosol
|
Mitochondrial Matrix
|
Activated Intermediates
|
Bound to ACP
|
Thioester of CoA
|
Enzymes
|
FAS is a multienzyme complex
|
4 distinct enzymes
|
Substrate
|
Acetly CoA
|
Fatty Acids
|
Direction
|
Starts at methyl end
|
Starts at the carboxyl end
|
Cofactors
|
NADPH
|
FADH/NADH
|
Major sites
|
Liver
|
Muscle and Liver
|
Hormonal Regulation
|
High Insulin/Glucagon ratio
|
Low Insulin/Glucagon ratio
|
Activator
|
Citrate
|
Free fatty acids
|
Inhibitor
|
Fatty acyl CoA
|
Malonyl CoA
|
