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Bi/Ch110 Final Review
Final Logistics
Biochemistry 110 – Final Exam
Fall 2016
• The final exam is open book (see allowed materials in the following bullet point) and the
time limit is 5 hours. Please indicate on your exam when you began the exam and when you
ended the exam (also indicating if/when you took a break during the exam). If you run out
of time, please indicate which questions you completed after the time limit was reached and
you can still receive half credit for questions completed after the time limit.
• For the final the exam, you may use the following materials:
-Your Stryer ‘Biochemistry’ textbook
-Your lecture notes and homework problem sets
-Any material that has been posted on the Biochemistry 110 website
-A calculator, Excel, Mathematica, etc. for calculations/plots
• You may have one break for any amount of time during the exam. During this break you
may not consult any Bi/Ch110 materials or talk to other students about the exam.
• Please have each problem of the exam on a separate page with your name on every page
of the exam. You may have multiple pages for the same problem but you must have your
name on every page.
• The due date is at noon in the Bi/Ch110 box located outside of Crellin 268 on Thursday,
December 8, 2016. The exam is due at noon sharp and we will begin grading the exam at
12:30pm. You may submit the exam any time before this time/date but not after.
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Final Exam Topics
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Proteins/Protein Structure
Enzymes/Catalysis
Glycolysis
Gluconeogenesis
Citric acid cycle
Oxidative phosphorylation
Photosynthesis
Fatty acid metabolism
Proteins and Protein Structure
You should know:
• Amino acids and their properties (not memorization of the amino acids)
• Levels of protein structure (primary, secondary, tertiary, quaternary)
• Experimental methods in protein structure determination
• Anfinsen’s protein folding experiment (what was it and what was the conclusion)
You should be able to:
• Understand and apply the different categorizations of amino acids: polar, hydrophobic,
charged
• Identify secondary and tertiary structure properties (e.g. what properties differentiate
alpha helices from beta-sheets)
• Identify methods of determining protein structure
Review material:
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-Amino Acid Sequence of a Protein Determines its Structure (from Scott Virgil’s slides)
-1950’s experiments by Christian Anfinsen demonstrated that a “denatured” protein possessed
the information in its sequence to refold into active enzyme. Experiment is detailed below:
Enzymes kinetics
You should know:
• What are the catalytic strategies of enzymes
• Michaelis-Menten kinetics (steady-state kinetics) application to enzymatic reactions
• Types of enzyme inhibitors
You should be able to:
• Describe what an enzyme is and how it catalyzes a reaction
• Draw out enzymatic mechanisms
• Identify the different enzyme inhibitors given kinetic data and describe the properties of
different inhibitors
• Draw out a reaction pathway for an enzyme with inhibitors
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Review material:
Enzymatic catalysis lowers the activation energy barrier of the reaction:
Enzymatic mechanisms (Shu-ou gave many examples in her slides in Lec 9 and Lec 10)
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Types of enzyme inhibitors:
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Glycolysis and gluconeogenesis
Glycolysis is the process that allows the simple sugar glucose, which comes from your food, to
be broken down into usable energy. It’s part of a larger process called cellular respiration.
Glycolysis -the simple sugar glucose is broken down in the cytosol
Pyruvate, the product from glycolysis, is transformed into acetyl CoA in the mitochondria in
preparation for the next step
The citric acid cycle - where electron carriers, NADH and FADH2, are made in the mitochondria
Oxidative phosphorylation - this process occurs in the mitochondria, and uses the electron
transport chain to produce ATP, the bulk of usable energy for the cell
What happens in glycolysis?
Over the course of several steps, glycolysis breaks down one glucose molecule into two
molecules of another compound called pyruvate. Pyruvate is essentially ½ of a glucose molecule
because it contains half the carbons from glucose. Glycolysis can be broken down into two
phases: the investment phase and the reward phase.
What happens in gluconeogenesis?
Now let’s say that you’re waking up from a nice 10 hour sleep. You haven’t eaten all night so
there is no (or very little) available glucose left in your body. Yet, your body still needs to have
energy to live and get you out of bed. One of the ways your body can produce the energy
(glucose) you need is by reversing the process of glycolysis. This reversal of glycolysis is called
gluconeogenesis. Instead of using carbohydrates to produce glucose, our body converts noncarbohydrate sources (like amino acids) in our liver into glucose. Our body then takes that
glucose and uses it to maintain our blood sugar at a constant, healthy level.
In glycolysis there are three irreversible steps. Since gluconeogenesis is glycolysis in reverse,
you can imagine that some roadblocks occur at the irreversible steps of the glycolysis pathway.
The irreversible steps of the glycolysis pathway release a lot of energy when they occur. In
contrast, performing these irreversible steps in the opposite direction during gluconeogenesis
requires a lot of energy, as the energy needed is equal to the energy that was released in the
forward reaction. Since the goal of gluconeogenesis is to produce emergency sources of energy
when you haven’t eaten food, there usually isn’t enough energy available. Instead, the cell has
come up with a roundabout way to still run gluconeogenesis (or to still run the reverse of
glycolysis) without requiring large amounts of energy. Only the irreversible reactions require
these roundabout ways, or detours, as the rest of the reactions are reversible and do not require
large amounts of energy, regardless of the direction of the reaction.
To summarize the two described pathways, please check out the table on next page:
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The Citric Acid Cycle
You should know:
• Cellular location of steps
• Reactants (ex. NAD+) and products (ex. ATP, CO2) for each step and the net reaction for
the pathway
• General mechanism for each step (ex. oxidation-reduction reaction vs. isomerization vs.
etc)
• Which enzymes are regulated and how
You should be able to:
• Link the citric acid cycle to other pathways discussed in class
• Discuss how various conditions (ex. high ATP, low O2) would affect the citric acid cycle
• Follow a carbon atom through the reactions of the citric acid cycle and related pathways
• Explain why certain enzymes are regulated
• Count ATP/NADH consumed/generated when various reactants/intermediates are entered
into a pathway
• Explain why a reaction is favorable/unfavorable (ex. why phosphoryl transfer has –ΔG)
• Apply your knowledge of the pathways we’ve studied to analyze a new pathway
Review material:
Fate of pyruvate generated by glycolysis:
The input for the citric acid cycle is acetyl CoA, and this is generated from pyruvate by pyruvate
dehydrogenase. This reaction takes place in the mitochondrial matrix.
The citric acid cycle oxidizes two-carbon units to CO2, producing one ATP and electrons, which
are carried by three NADH and one FADH2. These electron carriers generate ATP in oxidative
phosphorylation. The citric acid cycle begins with the addition of an acetyl group onto
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oxaloacetate and ends with the regeneration of oxaloacetate that can be used again in the next
cycle. These reactions take place in the mitochondrial matrix.
Overall reaction of the citric acid cycle:
acetyl CoA + 3NAD++ FAD + Pi+ ADP + H2O à
CoA + 3NADH + FADH2+ 2H++ ATP + 2 CO2
Regulation:
Pyruvate dehydrogenase is highly regulated by acetyl CoA, NADH, ATP, and phosphorylation
because it catalyzes an irreversible reaction. Isocitrate dehydrogenase and α-ketoglutarate
dehydrogenase are highly regulated by ADP/ATP, NAD+/NADH, their reactants/products, and
up/downstream matabolites because these are the first steps in the cycle that generate electrons
(NADH). The regulation of these steps can also shuttle metabolites to other pathways (ex. amino
acid synthesis) when energy is in excess.
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Oxidative Phosphorylation
What you should know:
-where the process takes place in a cell
-which reactants contribute to the electron transport chain and how the flow of electrons is
mediated (reduction potentials)
-which proteins are involved and how they contribute
What you should be able to do:
-understand how this process relates to the other metabolic processes
-track the flow of electrons
-explain what factors change its effectiveness
Review:
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The final step of aerobic respiration consists of electron transport along the mitochondrial
membrane (electron transport chain) and the generation of ATP through the phosphorylation of
ADP (chemiosmosis). These processes use the electrons produced from previous metabolic
processes in order to generate a proton gradient that ultimately forms ATP. Overall, the electronrich NADH and FADH2 which were formed as byproducts of earlier steps of respiration transfer
their electrons to carrier proteins along the inner mitochondrial membrane, and the flow of
electrons result in protons moving across the membrane. Ultimately, these proton transfers
generate a gradient of hydrogen ions that drive ATP production.
Electron Transport Chain
In essence, the electron transport
chain is a series of oxidationreduction reactions. NADH and
FADH2 are good electron
donors, while oxygen has a high
reduction potential which means
it makes a good electron
acceptor in the chain. As the
chain progresses, the reduction
potentials increase until oxygen
receives the electrons. The
transfer of electrons fuels proton
transfers from the matrix to the
intermembrane space.
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The chain has four complexes:
• Complex I (NADH-CoQ
oxidoreductase): NADH
transfers its electrons to
coenzyme Q (Q), which is catalyzed by this complex. This complex has many subunits,
but two important ones are a protein that has an iron-sulfur cluster and a flavoprotein
with a coenzyme called flavin mononucleotide (FMN). NADH transfers its electrons to
FMN, becoming oxidized to NAD+ as FMN is reduced to FMNH2. Next, the flavoprotein
is reoxidized and a series of Fe-S clusters are reduced. Lastly, the final reduced Fe-S
subunit donates its electrons to Q (aka ubiquinone). 4 protons are pumped into the
intermembrane space, and the net effect is Q getting reduced to QH2.
Complex II (succinate-CoQ oxidoreductase): As in complex I, complex II transfers
electrons to Q; however, complex II is unique in that is receives electrons from succinate
(which, when oxidized to fumarate in the citric acid cycle, reduces FAD to FADH2).
FADH2 gets reoxidized as it reduces an Fe-S protein, which then gets oxidized as Q is
reduced to QH2. No protons are pumped, and the net effect is the reduction of Q to QH2.
Complex III (CoQH2-cytochrome c oxidoreductase): This complex facilitates the transfer
of electrons from QH2 to cytochrome c, which happens over several steps involving the
oxidation and reduction of cytochromes (proteins with heme groups where Fe is reduced
to Fe2+ and reoxidized to Fe3+. Only one electron is transferred per iron, but since QH2
has two electrons to transfer, two cytochrome c molecules are needed. The Q cycle
happens in this complex as well. In the first half of the cycle, QH2 transfers one electron
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tl;dr
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to cytochrome c, which results in 2 protons being pumped into the intermembrane space.
The other electron binds to a Q in another binding site. In the second half of the cycle,
another QH2 transfers one electron to cytochrome c and one to a Q, resulting in 2 more
protons being pumped out and two protons being taken up into the complex, in addition
to the formation of QH2. QH2 then can enter the Q pool of the membrane. Thus, the net
result is the transfer of two protons into the intermembrane space per QH2.
Complex IV (cytochrome c oxidase): This complex is responsible for the transfer of
electrons from cytochrome c to oxygen, the last electron acceptor. The complex contains
many subunits of cytochrome a, cytochrome a3, and Cu2+ ions. Two molecules of
cytochrome c transfer electrons to reduce Fe and Cu. These reduced ions bind O2,
forming a peroxide bridge. Adding in two more electrons results in the cleavage of the
bridge, and the uptake of two protons results in the formation of water. Overall, 4
cytochrome c electrons are needed to reduce oxygen to water, and four protons are
pumped as a result.
Complex I
o NADH + H+ + FMN à NAD+ + FMNH2
o FMNH2 + 2 Fe-Soxidized à FMN + 2 Fe-Sreduced + 2 H+
o 2 Fe-Sreduced + Q + 2 H+ à 2 Fe-Soxidized + QH2
Complex II
o Succinate + FAD à fumarate + FADH2
o FADH2 + Fe-Soxidized à FAD + Fe-Sreduced
o Fe-Sreduced + Q + 2 H+ à Fe-Soxidized + QH2
Complex III
o QH2 + 2 cytochrome c (with Fe3+) à Q + 2 cytochrome c (with Fe2+) + 2 H+
Complex IV
o 4 cytochrome c (with Fe2+) + 4 H+ + O2 à 4 cytochrome c (with Fe3+) + 2 H2O
Overall, [H+] increases in the intermembrane space, which decreases pH and increases the
voltage difference between the intermembrane and the matrix, creating an electrochemical
gradient which is also known as the proton-motive force.
Chemiosmosis
Since protons cannot directly pass through the
membrane, they go through ATP synthase. ATP
synthase comprises two subunits:
F0 subunit: this functions as a proton channel,
allowing for protons to travel along the gradient from
the intermembrane space through the inner
mitochondrial membrane and back into the matrix.
F1 subunit: this is the portion of ATP synthase that
utilizes the energy released from the electrochemical
gradient to phosphorylate ADP to ATP. Acting like a
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turbine, an ADP molecule first binds to the subunit, gets phosphorylated, then is released as
ATP. The rotor itself has three states which arise from conformational changes of the alpha and
beta subunits:
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the “loose” conformation: ADP and Pi bind reversibly
the “tight” conformation: formation of ATP
the “open” conformation: release of ATP
It takes about 3.3 protons to form 1 ATP.
Photosynthesis
You should know:
• Cellular location of the steps
• Reactants and products for each step and the net reaction for the pathway
• General mechanisms for each step (ie oxidation-reduction reaction vs isomerization)
• Which enzymes are regulated and how
You should be able to:
• Link photosynthesis to other pathways discussed in class
• Draw analogous pathways
• Discuss how various conditions (ex…) would affect photosynthesis and how these constraints
have led to the evolution of different types of photosynthesis
• Follow a carbon atom from CO2 to the …
• Explain why certain enzymes are regulated
• Count ATP and FADH2 produced vs. consumed
• Explain why a reaction is favorable or unfavorable
• Be able to use these skills to analyze a new pathway
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Review Material:
Overall reaction of Photosynthesis:
Regulation:
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Accessory pigments
Energy transfer from accessory pigment to reaction center
Cyclic electron flow through photosystem I
Photosynthesis, oxidative phosphorylation
Rubisco
Ferrodoxin-NADP+ reductase
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What occurs when a photon of light energy is absorbed?
The energy of the photon is absorbed, and the photon disappears. Photon absorption boosts an
electron from ground state to a higher orbital, in an all-or-none fashion. An "excited state"
pigment is produced, with a higher energy level than the ground state pigment, but this excited
state is very short-lived, about a billionth of a second.
Conversion of light energy to chemical energy
Light energy is converted to chemical energy when a photochemically excited special
chlorophyll molecule of the photosynthetic reaction center loses an electron, undergoing an
oxidation reaction.
Photosynthesis equation
The overall result of photosynthesis in plants (i.e. light and dark reactions) is summarized in the
equation of photosynthesis.
Water is oxidized to oxygen. The electrons from water are first used to reduce NADP+ to
NADPH. NADPH is subsequently reoxidized during the reactions of carbohydrate biosynthesis
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of the Calvin Cycle. The overall fate of the electrons from water is in the reduction of carbon
dioxide.
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Fatty Acid Metabolism
Motivation: Understand the process by which fatty acids are synthesized and broken down and
why this process is important.
Why is fatty acid metabolism useful?
- The complete oxidation of fatty acids yields 9 kcal g-1 compared to the 4 kcal g-1
from burning carbohydrates and proteins.
- A gram of anhydrous fat stores 6.75 times as much energy as a gram of hydrated
glycogen
Fatty acids have four major physiological roles:
1. Fatty acids are fuel molecules (stored as triacylglycerols); uncharged esters of fatty acids
with glycerol
a. During rest, fatty acids are the primary source of energy
2. Fatty acids are building blocks of phospholipids and glycolipids
a. Components of biological membranes
3. Proteins are modified by the covalent attachment of fatty acids, which targets the proteins
to membrane locations
4. Fatty acid derivatives serve as hormones and intracellular messengers
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Where is the energy derived from?
1) Fatty acids are in a much more reduced state than carbohydrates or proteins
2) Their nonpolar nature allows them to be nearly anhydrous (higher energy density)
a) Consider a 70 kg man. If 11 kg of triacylglycerols were stored in glycogen, his
total body weight would be 64 kg greater.
b) Glycogen and glucose stores provide energy to sustain physiological function for
about 24 hours whereas triacylglycerol stores allow survival for several weeks
Fig 1. Energy associated with various carbon oxidation states.
Why are fatty acids linked to coenzyme A before oxidation?
- Activation allows fatty acids to enter the mitochondria for oxidation (which occurs in the
outer mitochondrial membrane by acyl CoA synthetase)
These partial reactions are freely reversible (one high-transfer potential compound is cleaved and
one high-transfer potential compound is formed). How is the overall reaction driven forward?
Effectively generate 2 equivalents of PPi
Transfer of the fatty acid into the mitochondrial matrix:
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Fig 2. Acyl carnitine translocase that allows the entry of acyl carnitine into the mitochondrial
matrix; mechanism hinges on the zwitterionic nature of carnitine which allows solvation distinct
from normal alcohols.
Degradation of Fatty Acids
Fig 3. Degradation of triacylglycerol and their fate in other cells.
We will consider two cases of β-oxidation (reaction named since oxidation occurs at the β
carbon):
Case 1: Even numbered carbon atom fatty acids
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Fig 4. Reaction sequence for the degradation of fatty acids with even number of carbons.
Notes: the trans-ene is formed
FAD rather than NAD+ is the electron acceptor because △G for this reaction is insufficient
to drive the reduction of NAD+
Hydration of enoyl CoA is stereospecific
Fig 5. 1.5 molecules of ATP/FADH2 are generated in the dehydrogenation step.
Table 1. Principal reactions in fatty acid oxidation
Case 2: Unsaturated and odd-chain fatty acids (palmitoleate)
- require additional steps for degradation
- Specifically, an isomerase and a reductase are required for complete oxidation
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Fig 6. Degradation of the monounsaturated fatty acid palmitoleoyl CoA (left) and oxidation of
the di-unsaturated fatty acid linoleate CoA (right).
Palmitoleate:
The problem: cis-△3-Enoyl CoA is not a substrate for acyl CoA dehydrogenase.
The solution: A new reaction shifts the position and configuration of the cis-△3 double
bond (cis-△3-Enoyl CoA isomerase)
Linoleoyl
The problem: on top of having to deal with the cis-△3 double bond (whose solution is
described above), after another round of β-oxidation, a cis-△4 double bond is formed
yielding a 2,4-dienoyl intermediate following dehydrogenation.
The solution: 2,4-dienoyl CoA reductase is utilized, leveraging NADPH to reduce 2,4dienoyl intermediate to trans-△3-enoyl CoA. cis-△3-Enoyl CoA isomerase then converts
the trans-△3-Enoyl CoA substrate to the trans-△2 form
Overall: Odd-numbered double bonds are handled by the isomerase and even-numbered double
bonds by the reductase and isomerase
Odd-chain fatty acids:
Same process as even-chain fatty acids, except: propionyl CoA and acetyl CoA rather than two
molecules of acetyl CoA are produced in the final round of degradation.
- The activated three carbon unit in propionyl CoA enters the citric acid cycle after
conversion to succinyl CoA with aid from vitamin B12
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Fig 7. Conversion of propionyl CoA to succinyl CoA
Notes on this pathway: Proponyl CoA carboxylase catalyzes the carboxylation reaction
- Mutase converts it into the L isomer
- Intramolecular rearrangement converts the L isomer of methylmalonyl CoA into succinyl
CoA (methylmalonyl CoA mutase)
- If you are interested in the mechanism, which involves cobalamin, I suggest reading pg
655-656 in the text.
- The role of B12 is to serve as the source of free radicals for the abstraction of
hydrogen atoms
Differences between the synthetic and degradative pathways of fatty acids:
1) Synthesis takes place in the cytoplasm whereas degradation takes place primarily in the
mitochondrial matrix.
2) Intermediates in fatty acid synthesis are covalently linked to the sulfhydryl groups of an
acyl carrier protein, whereas intermediates in fatty acid breakdown are covalently
attached to the sulfhydryl group of coenzyme A.
3) The enzymes of fatty acid synthesis in higher organisms are joined in a single
polypeptide chain called fatty acid synthase. In contrast, the degradative enzymes are not
linked covalently.
4) The growing fatty acid chain is elongated by the sequential addition of two carbon units
derived from acetyl CoA. The activated donor of two-carbon units in the elongation step
is malonyl ACP. The elongation reaction is driven by the release of CO2.
5) The reductant in fatty acid synthesis is NADPH, whereas the oxidants in fatty acid
degradation are NAD+ and FAD.
6) The isomeric form of the hydroxyacyl intermediate in degradation is L while the D form
is used in synthesis.
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Fig 8. Comparison of fatty acid degradation and synthesis.
Fig 9. Steps of fatty acid synthesis.
One catalytic cycle (shown above):
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1) Malonyl/acetyl transacylase (MAT) moves an acetyl unit from coenzyme A to the acyl
carrier protein (ACP).
2) β-Ketosynthase accepts the acetyl unit to form a thioester with a cysteine residue at the
β-KS active site.
3) The vacant ACP is reloaded by MAT, this time with a malonyl moiety. The two are
condensed at β-KS with the concomitant release of CO2.
4) The loaded ACP then delivers the β-ketoacyl product to the KR enzyme, which reduces
the keto group to an alcohol.
5) The β-hydroxyl product then visits the dehydrogenase, which introduces a double bond
with the loss of water.
6) The enoyl product is delivered to the ER enzyme, where the double bond is reduced
7) ACP hands the reduced product to KS and is recharged with malonyl CoA by MAT
8) KS condenses the two molecules on ACP, which is now ready to begin another cycle
Fig 10. Transfer of acetyl CoA to the cytoplasm for fatty acid synthesis.
Citrate carries acetyl group from mitochondria to the cytoplasm for fatty acid synthesis
- fatty acid synthesized in the cytoplasm
- CoA formed from pyruvate in mitochondria
Note: Barrier of acetyl CoA is bypassed by citrate, which carries acetyl groups across the inner
mitochondrial membrane
- citrate formed in the mitochondrial matrix by the condensation of acetyl CoA with
oxaloacetate
- Once in the cytoplasm, citrate is cleaved by ATP-citrate lyase
Note: Interplay between citrate, which inhibits phosphofructokinase in the glycolytic pathway,
and fatty acid synthesis
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Sources of NADPH for fatty acid synthesis:
1) Oxaloacetate is reduced to malate by NADH (malate dehydrogenase)
2) Malate is oxidatively decarboxylated by an NADP+-linked malate enzyme (malic
enzyme)
3) Pyruvate formed pyruvate formed in this reaction readily enters mitochondria, where it is
carboxylated to oxaloacetate by pyruvate carboxylase
Thus, one molecule of NADPH is generated for each molecule of acetyl CoA that is transferred
from mitochondria to the cytoplasm
Fatty acid synthesis stems from the coordination of multiple pathways:
- Citric acid cycle transports oxaloacetate from the mitochondria
- Pentose phosphate pathway provides the carbon atoms and reducing power
- Glycolysis and oxidative phosphorylation provide the ATP to meet the needs for fatty
acid synthesis
Regulation of Fatty Acid Metabolism
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Formation of malonyl CoA is the committed step in fatty acid synthesis (in the
mitochondria)
Acetyl CoA carboxylase 1 and 2 catalyzes the committed step in fatty acid synthesis:
production of malonyl CoA
Two modes of regulation: conditions in the cell and hormonal control
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Fig 11. Deactivation by phosphorylation and activation by dephosphorylation. AMP-activated
protein kinase converts the carboxylase into an inactive form by modifying three serine residues,
activated by AMP and inhibited by ATP
Carboxylase allosterically stimulated by citrate
- signals that raw materials and energy is available for fatty acid synthesis
Citrate facilitates the polymerization of the inactive dimers
- Partly reverses the inhibition produced by phosphorylation
The stimulatory effect of citrate is counteracted by palmitoyl CoA, which is abundant when there
is an excess of fatty acids
- inhibits translocase that transports citrate from mitochondria to the cytoplasm, as well as
glucose 6-phosphate dehydrogenase which generates NADPH in the pentose phosphate
pathway
Malonyl CoA inhibits carnitine acyltransferase I, preventing the entry of fatty acyl CoAs into the
mitochondrial matrix in times of plenty
Hormonal regulation
- glucagon, epinephrine, insulin
- Insulin stimulates fatty acid synthesis by activating the acetyl CoA carboxylase
by enhancing the phosphrylation of AMPK by protein kinase B as well as by
stimulating the activity of a protein phosphatase that dephosphorylates and
activates acetyl CoA carboxylase, whereas glucagon and epinephrine have the
reverse effect
- Glucagon and epinephrine present conditions of fasting and exercise. Inhibit fatty
acid synthesis by inhibiting acetyl CoA carboxylase; augment the inhibition by
the AMP-activated kinase; keep the carboxylase in the inactive phosphorylated
state
Elongation and Unsaturation of Fatty Acids are Accomplished by Accessory Enzyme
Systems
- Fatty acids are elongated and desaturated by enzyme systems in the endoplasmic
reticulum membrane
- Desaturation requires NADH and O2 and is carried out by a complex consisting of a
flavoprotein, a cytochrome, and a nonheme iron protein
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Double bond formed and two molecules of H2O released. Two electrons come from NADH and
two from the single bond of the fatty acyl substrate
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