acid oxidation Flashcards

Terms Definitions
Short Chain FA
4C
Coenzyme A
What is CoA-SH?
hydroxyacyl
another dehydrogenase catalyzes oxidation of __________ group and forms two double bonds. NAD+ is the cofactor. This forms Ketoacyl-CoA.
TFP
substrate channeling heterooctamer in B-oxidation pathway
example of a monousaturated fat
oleate(c18:1)
NADH
By-product of Hydroxy-acyl CoA dehydrogenase reaction
enoyl-CoA
_____-_____ hydratase adds water molecle to the enoyl-CoA
acyl-CoA dehydrogenase
enzyme to conversion from Palmitoyl-CoA to trans(delta)2-Enoyl-CoA
B-hydroxyacyl-CoA dehydrogenase
enzyme to conversion from L-B-Hydroxy-acyl-CoA to B-ketoacyl-CoA
makes the basic structure of sphingolipids and composed of a FA chain joined to a sphingosine via an amide linkage
Creamide
HMG-CoA lyase
HMG-CoA -> acetoacetate + Acetyl-CoA
3 Acetyl-CoA ->
HMG-CoA + 2 CoASH
FADH2
By-product of Fatty acyl dehydrogenase reaction
acetyl- CoA
next, the activated thioester undergoes four more steps in the reaction sequence, oxidation, hydration, oxidation, and cleavage, to produce __________ and an activated thioester shortened by two carbon atoms
Step 4: Thiolysis
Beta-ketothiolase catalyzes thiolytic cleavage and acetyl-CoA is released, yielding fatty acyl-CoA (2 Carbons less).
H2O CoA-SH
What substrates are introduced into the B-oxidative pathway?
Enoyl Co-A hydratase
enzyme to conversion from trans(delta)2-Enoyl-CoA to L-B-Hydroxy-acyl-CoA
lipid class derived from an aliphatic alcohol
Sphingolipids
Primary carnitine deficiency is equal to what
transporter fefects
Carnitine acylcarnitine translocase
Moves fatty acylcarnitine through inner mitochondial membrane. Moves carnitine out of inner mitochondrial space.
Thiolase
Enzyme used for Keto-acyl CoA => fatty-acyl CoA
aerobic
fatty acid oxidation _____ because the products, FADH2 and NADH can be reoxidized only when oxygen is present.
step 4
Oxidation (dehydrogenation of carbon 3 (beta carbon) to a keto group
Acyl-CoA Synthetases
Catalyze activation of long chain fatty acids, esterfying them to coenzyme A. This process is ATP dependent and occurs in 2 steps. There are different Acyl-CoA synthetases for fatty acids of different chain lengths. Acyl-CoA traps the fatty acid in the cell.
Fatty Acids
What is oxidized in the B-oxidative pathway?
Zellwger's Syndrome
Very long chain fatty acids accumulate in the tissue and blood. This causes complex developmental and metabolic changes which mainly affect the liver and the brain. It is caused by a general defect in the biogenesis of peroxisomes in all tissues.
Ketone Bodies
Synthesized in the mitochondria of the liver. The raw material for their synthesis is acetyl-CoA produced by the breakdown of fatty acids by beta-oxidation
Hormone sensitive lipase
During fasting and exercise this enzyme is activated
2 ATP
activation of fatty acids requires __ _____ equivalents per fatty acid molecule
4
how many ATP will be produced from one pass of B-oxidation?
FA classification and metabolism routes depend on what?
the chain length (enzyme specific)
Very long chain fatty acids
Mitochondrial Beta-oxidation is unable to deal with FA having a chain length of greater than 20 carbons. Must undergo preliminary beta-oxidation in the peroxisomes. Peroxisome oxidation proceeds until the acyl chain have been reduced in length to medium or short chains.
beta oxidation involves 4 steps, these compounds are created
FADH2 and NADH
(=) (n/2)-1
FADH2 and NADH yield for for fatty acyl CoA chain length nC
FADH2 and NADH
No ATP is directly produced during fatty acid catabolism. instead, ATP forms with the reduction of ______ ____ _____ are oxidized by the mitochondrial electron-transport system in concert with oxidative phosphorylation.
Carnitine
Binds the acyl group from Acyl CoA in the cytoplasm and transports it through a translocase to the mitochondria where the Acyl goes back to CoA making acyl-CoA. Control of fatty acid oxidation is done at this step. Malonyl Co-A inhibits Carnitine Palmitoyl Transferase I (thus blocking transport to the mitochondria).
FADH NADH
What are the by products of the B oxidative pathway?
What does B oxidation yield
NADH, FAD (2H), & acetyl CoA.
Carnitine palmitoyl-transferase (CPTI)
Fatty Acyl CoA + Carnitine -> Fatty acylcarnitine (CoA)
Carbon Molecules of Fat
Form 2 Carbon units; every cut makes energy
FFA disrupt peptide side chains so what are they mostly bound to
PLASMA PROTEINS IN THE CIRCULATION
decreased levels of carnitine are associated with what?
Alzheimer and agine; also type 2 diabetes; HIV; cancers
First step, free fatty acids must become bound to
Acetyl CoA to become fatty acyl-CoA derivatives
How do FA get in to the cytosol
FA binding proteins, this is an ATP step that requires CoA
long chain FA
12-20
2 acetyl-CoA
Acetoacetate+ 2 CoASH
3-hydroxyacyl-CoA
_____________ dehydrogenase removes two hydrogen atoms from the hydroxyacyl-CoA
very long chain FA
> 20
ketoacyl-CoA
_______-__ thiolase releases the sulfur (thiol)-containing acetyl-CoA
Step 3: Oxidation
Hydroxyacyl-CoA dehydrogenase catalyzes oxidation of the hydroxyl in the Beta-position (C3) to a ketone. NAD+ is the electron acceptor.
Acetyl-CoA
B oxidation pathway products: name short-chain product
palmitoyl-CoA
first molecule of B oxidation pathway
name secondary condition of carnitine
renal failure
HMG-CoA synthase
Acetyl-CoA + acetoacetyl-CoA -> 3-hydroxy 3-methylglutaryl-CoA(HMG-CoA) +CoASH
Refsum's Disease
Rare autosomal recessive genetic disorder in which alpha-oxidation is impaired. It results in neurological problems is due to build up of phytanic acid, a multi-methylated fatty acid, in the blood and particularly in the membranes of nervous tissue cells. This build up interferes with the normal conductivity and functioning of the nerve cells.
Acetoacetyl-CoA thiolase
Acetyl-CoA + Acetyl-CoA -> Acetoacetyl-CoA + CoASH
to breakdown palmitate requires how many cycles of beta oxidation?
7
step 2
Oxidation (dehydrogenation at carbons 2 and 3 (alpha and beta carbons)
thioester
compound containing an ester linkage to a sulfur rather than an oxygen atom
Step 1: Oxidation
Acyl-CoA dehydrogenase catalyzes oxidation of the fatty acid of acyl-CoA to produce a double bond between carbon atoms 2 and 3. FAD is the electron acceptor.
Step 2: Hydration
Enoyl-CoA hydratase catalyzes hydration of the tans double bond produced in step 1, yeilding hydroxyacyl-Coenzyme A.
trans-delta-2 Enoyl-CoA
2nd intermediate of B oxidation pathway
8
how many acetyl-CoA will be produced from B-oxidation of stearic acid?
What is sphingolipidoses
disorders of sphingolipid metabolism affecting neural tissue
hydrophobic, wart insoluble and cytotoxic
characteristics of fats
Ketoacidosis
H+ are produced along with ketone bodies. If the buffering capacity of the blood is overwhelmed this condition will occur.
Lipase
Fatty acid => Fatty acyl CoA (enzyme)
acyyl- CoA dehydrogenase
____ ____ ________catalyzes oxidation of acyl group
2
How many electrons are produced in a round of B-oxidation
Jamaican Vomiting Sickness
Hypoglycin in fruit inhibits medium and short chain acyl-CoA dehydrogenases. Beta-oxidation is diminished and patient becomes hypoglycemia, glucose used not fatty acids. Gluconeogenesis impaired because energy is normally supplied by beta-oxidation.
fatty acyl-CoA is transported into the mitochondria by
carnitine shuttle
(=>) Keto-acyl CoA
Hydroxy-acyl CoA => (Hydroxy-acyl CoA dehydrogenase)
1
How many NADH are produced in 1 cycle of B-oxidation?
Name some conditions of primary carnitine deficiency
cardiomyopathy, muscle weakness, hypoglycemia
Medium chain-acyl-CoA dehydrogenase deficiency (MCAAD)
Deficiency of the mitochondrial medium chain acyl-CoA dehydrogenase. Diminished beta-oxidation, hypoglycemia (seizures and coma). Acyl-carnitines and dicarboxylic acids found in urine. Infants particularly vulnerable (milk diet), treated with low fat, carbohydrate rich diet.
(=) n/2
CoA yield for fatty acyl CoA chain length nC
oxidation, hydration, oxidation, and cleavage
next, the activated thioester undergoes four more steps in the reaction sequence, ______,_______,_______,_______ , to produce acetyl CoA and an activated thioester shortened by two carbon atoms
Fatty Acid Oxidation
The pathway for catabolism of fatty acids. Alsoknown as the Beta-oxidation pathway because oxidation occurs at the beta-carbon. It is a reoccuring sequence of 4 reactions: oxidation (leading to reduction of FAD), hydration, oxidation (leading to reduction of NAD+), & thiolysis. This results in the shortening o the fatty acid by 2 carbons. The acetyl CoA generated can enter the citric acid cycle and the NADH and FADH2 can enter the ETC. Note: it occurs in most cells except the brain.
Formation of ATP
Acetyl CoA moves to TCA Cycle; Those products combine with products from each "cut" and move to ETS
Carnitine palmitoyl transferase II (CPT II)
Fatty acylcarnitine (CoA) -> Fatty acyl CoA + Carnitine
What is the function of carnitine
transport activated fatty acyl groups across the inner mitochondrial membrane
Why do we store fat?
Fat yields much more energy than sugar does.
Name the rate limiting enzyme of b oxidation; it catalyzes the formation of fatty acyl carnitine
Fatty acyl carnitine transferase I
two things to know about beta oxidation of monounsaturated fatty acids
yields less energy, requires enzyme to move double bond to appropriate place
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