Fatty Acids Flashcards
First important regulatory point in fatty acids beta-oxidation is the?
carnitine/acyl
carnitine shuttle
Regulation of β-oxidation: what is the rate limiting step of fatty acid oxidation?
The carnitine shuttle
fatty acids that enter the mitochondrial are destined for?
β-oxidation
What is the first intermediate produced during fatty acid
synthesis
malonyl CoA
What inhibits the enzyme carnitine acyltransferase l and therefore blocks β-oxidation from
proceeding
Malonyl CoA
Which transcription factor also promotes transcription of genes required to break down fats
CREB
Biosynthesis of macromolecules is?
reductive and endergonic (energy requiring process
What usually serves as the reducing agent
NADPH
What are the primary component of
triacylglycerols and phospholipids of cell membranes
and other cellular components (i.e. biologically
Fatty acids
Reducing agents in B-oxidation?
FAD
NAD+
Metabolites produced due to high levels of NADH compared to NAD inhibit what enzyme?
B-hydroxyacl CoA dehydrogenase
Which enzyme does acetylCoA inhibit?
Thiolase
What enzyme catalyses the formation of malonyl CoA
Acetyl CoA carboxylase
What phosphorylates and inactive ACC?
cAMP-dependent protein kinase
……..phosphorylates several targets e.g Acetyl CoA Carboxylase
AMP activated kinase (AMPK)
What happens when acetyl CoA is phosphorylated?
It becomes inactivated and switched off
Why will defects on fatty acids oxidation impart carbohydrate metabolism
Because metabolic pathways are LINKED
Chain growth is Catalysed by a set of…..enzymatic reactions called….
E enzymatic reactions
Fatty Acid synthase System (FAS)
……have the FAS I-multifunctional enzymes with domains with 7 active site.
Mammals
What are the reducing agents for beta oxidation
How is Thiol group (-SH of cys residue of enzyme) of ACP and KS (beta-ketoacyl-ACP synthase) charged?
Charged by being condensed with malonyl CoA and AcetylCoA respectively.
What enzyme transfers malonyl CoA to -SH of ACP?
Malonyl CoA transferase (MT)
What enzyme foes this. Acetyl CoA is transferred to -SH B-ketoacyl CoA ACP?
Acetyl CoA transacetylase . AT
Mention thd first way of chain lengthing and what catalyses it?
B-ketoacyl synthase (KS)
Is malonyl coA a good nucleophile?
Yes. Loves things with positive charge
What is the product of the first chain elongation step?
Acetoacetyl-ACP
Name the second step and what catalyses it? What it’s reduced to and its electron donor?
- Reduction of carbonyl group
- B-ketoacyl-ACP Reductase
- D-B-hydroxylbutyryl-ACP
- NADPH
Name the third step and what catalyses it? What its formed to and on which carbons does it occur?
Dehydration
B-hydroxylacyl-ACP dehydratase
Trans-◇^2-butenoyl-ACP
C2 C3
Set of 4 reactions occur when substrate is bound at the…..
ACP
After these reactions the chain is translocation to…..
KS where the acetylCoA had been at the beginning of the reaction).
What is the point of tranlocating the chain to KS….
To free up ACP-SH to take up and charge another malonyl CoA.
How many carbons are added to lengthen the fatty acid chain during each set of reaction?
2 carbons
How many sets if reaction form palmitate (16Carbons)
7
List 2 essential fatty acids?
Linoleate
Alpha linolenic acid
What are the precursors for monounsaturated fatty acids?
Palmitate
Stearate
Desaturated of fatty acid chains requires oxidative reactions of mixed function oxidase called….
Fatty acyl CoA desaturase
What makes up chylomicrons?
Apolipoproteins, cholesterol, triacyglycerols
What covers the surface of the chylomicron?
Phosphodiester head groups of the triacylglycerols
Which lipoprotein serve as recognition sites for transport and metabolism
Lipoprotein B-48, C-II, C-II
What makes up 80% of the chylomicron?
Fatty acid chains
What activates lipoprotein lipase?
Apolipoprotein C-II
Function of lipoprotein lipase?
Converting triacylglycerols to fatty acids and glycerol
Function of perilipins?
Prevent lipid droplets from untimely lipid mobilization
Hormones response for low glucose levels
Glucagon and epinephrine
What phosphorylates perilipins and what do phosphorylated perilipins interact with?
Name the active sites of alpha chains?
B-enoyl-CoA hydratase
B-hydroxyl CoA dehydrogenase
Active sites of beta chains?
Thiolase
How many ATPs are formed per 1 cycle of fatty acid oxidation?
4 ATPS
1 FADH2= 1.5 ATP
1 NADH= 2.5 ATP
TOTAL= 4 ATP
WHERE 2 CARBON UNITS ARE REMOVED
Coenzyme A is needed to continue B-oxidation. How is more Coenzyme A Freed up?
By converting Acetyl CoA to ketone bodies.
Ketone bodies are acidic hence reduce blood pH causing acidosis
