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Exam 2
Fatty Acid, Amino acid and CAC
127
Biochemistry
Undergraduate 2
02/26/2011

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Term
What are the 5 substrates of Pyruvate DH complex
Definition
TPP, Lipoate, CoA, FAD, NAD
Term
What are PDH parts and prosthetic groups?
Definition
E1-TPP
E2-Lipoate
E3-CoA, FAD, NAD
Term
What is the fate of glycerol?
Definition
converted into glycerol-phosphate, than DHAP to G3P
Term
What are the domains of E2 in PDH complex?
Definition
Binding, acyltransferase, lipoyl
Term
What part channels the substrate in PDH
Definition
Lipoyl group
Term
What does E1 PDH do?
Definition
decarboxylates pyruvate, TPP
Term
What does E1 PDH do?
Definition
decarboxylates pyruvate, TPP
Term
What does E2 in PDH do?
Definition
(Dihydrolipoyl transacetylase) Lipoate
and CoA as coenzyme,forms an
acetyl thioester and transfers the acyl group to CoA.
Term
What does E3 in PDH do?
Definition
(Dihydroxylipoyl dehydrogenase), with FAD and NAD+ as cofactor, regenerates the oxidized lipoyl group
Term
Why is Thiamine important?
Definition
lack of causes no PDH and therefore more lactate, brain uses PDH for most energy production
Term
What is an anaplerotic pathway?
Definition
pathway which regenerates the intermediates for CAC
Term
Where do the carbons come from after the first CAC turn?
Definition
not acetate from acetyl-CoA, comes from the old OAA
Term
What does cholecystokinin signal?
Definition
fat in stomach, releases bile salts for emulsification also release of proteolytic enzymes
Term
What does Pancreatic lipase do?
Definition
partially emulsifies TAGs into DAGs, and MAGs.
Term
Lipo proteins as packaged into what for transportation?
Definition
chylomicrons
Term
What does Apolipoproteins do?
Definition
activate lipase which turn chylomicrons into fatty acids
Term
What protein blocks the lipase from attacking stored TAGs?
Definition
perilipin
Term
How does Glucagon and epinephrine allow lipases to attack stored TAGs?
Definition
the activate the cAMP pathway which leads to phosphorylation of perilipin.
Term
What enzymes convert FFA to acyl-CoA?
Definition
fatty acyl-CoA synthetases
Term
What are the three end points of Fatty acyl-Coa?
Definition
membrane lipids, TAGs and oxidation in mito.
Term
What are the steps/pathway needed to transport FA into mito?
Definition
Carnitine Shuttle. FFA-acylCoA which is converted to a Carnitine ester by carnitine-acyltransferase I. Then converted back once inside.
Term
What blocks carnitine-acyl CoA?
Definition
Malonyl-CoA (first step in synthesis.)
Term
What are the 3 stages of FA oxidation?
Definition
1.) Beta-oxidation
2.) acetyl groups go through CAC
3.) oxidative phosphorylation
Term
How many steps are in Beta-oxidation?
Definition
4 steps, breaking bound at the beta carbon. by converting the Beta carbon into a ketone it is attacked
Term
What are the 4 enzymes in Beta-oxidation?
Definition
Acyl-CoA dehydrogenases,
Enoyl-CoA hydratase, L-β-hydroxyacyl-CoA dehydrogenase, and thiolase
Term
what does TFP do?
Definition
trifunctional protein channels the end of Beta-oxidation and is attached to the inner mito membrane
Term
Which enzymes are the alpha and beta parts of TFP?
Definition
alpha- enoyl-CoA
hydratase and β-hydroxyacyl-CoA
dehydrogenase
beta- thiolase
Term
What are the end products of each pass in Beta-oxidation?
Definition
4 ATP, 1 molecule of H2O, and one acetyl-CoA.
Term
What enzyme corrects unsaturated FAs?
Definition
Δ3,Δ2-enoyl-CoA
isomerase
Term
what three enzymes convert propionyl-CoA to succinyl CoA?
Definition
propionyl-CoA carboxylase and Methylmalonyl-CoA epimerase Methylmalonyl-CoA mutase
Term
what is pernicious anemia.
Definition
lack of B12, cant metabolize odd number FAs
Term
What is unique about B12 reactions?
Definition
add the adenosine allowing the three Phosphates to fall off.
Term
what does acetyl-CoA carboxylase contain?
Definition
3 parts: biotin carboxylase, biotin carrier protein and transcarboxylase
Term
how many domains does Fatty acid synthase type I?
Definition
two. create to FA at the same time.
Term
what four steps are repeated to add acetyl-Coa to FA?
Definition
attack of main chain, reduction, dehydration, reduction
Term
Fatty acid synthase type I is stopped by what?
Definition
thioesterase, after 7 cycles 16 carbons added
Term
Differences between ACP and CoA
Definition
ACP long bound protein has 4′-phosphopantetheine prosthetic group , CoA small soluble protein
Term
What does FA synthesis occur in plants/animals?
Definition
chloroplasts/cytoplasm
Term
Where does FA oxidation occur? plants and animals
Definition
pexosomes/mitochondria
Term
What is needed to add 2 carbons to a FA chain?
Definition
1 ATP and 2 NADPH + 2 H+ before transportation 3 ATP + 2 NADPH + 2 H after getting it out of mito
Term
Can mammals produce unsaturated FA?
Definition
yes only C-16 and C-18 at carbon 9. cant between 10 and methyl though.
Term
How does Citrate regulate FA?
Definition
activates acteyl-CoA carboxylase producing malonyl-CoA
Term
What does Palmitoyl-CoA regulate FA?
Definition
inhibites acteyl-coa carboxylase halting FA synthesis
Term
what is the regulation of Acyl-coa carboxylase by hormones?
Definition
Glucagon and epinephrine trigger phosphorylation and inhibition of acetyl-CoA carboxylase insulin does reverse
Term
how are the enzymes in Beta-oxidation regulated?
Definition
high [NADH]/[NAD+] inhibits β-hydroxyacyl-CoA
DH and high [acetyl-CoA] inhibits thiolase
Term
AMP-dependent kinase (AMPK) which does what?
Definition
phosphorylates and inhibits ACC
Term
What are two long term regulations of FA metablosim?
Definition
Glucagon, through the transcription factor CREB and PPAR (Peroxisome Proliferator-Activated Receptors),
Term
What does PPAR (Peroxisome Proliferator-Activated Receptors do?
Definition
stimulates production of oxidizing enzymes
Term
What is the difference between mito and pexosome/glyoxysome oxidation?
Definition
p and G pass electrons straight to O2, in H2O2. has high concentration of catalase need to export NADH and acetyl-coa to mito
Term
where does omega-oxidation occur?
Definition
ER of liver/kidney
Term
What is unique bout omega-oxidation?
Definition
gives off succinate (carb from FA) and oxidation from both ends
Term
What is alpha oxidation used for?
Definition
branched FA
Term
alpha-oxidation leads to carbs how?
Definition
breaks off a propionyl acid and that leads to succinyl-CoA
Term
what are the reasons for using ketone bodies?
Definition
free up CoA in liver and to transport energy to muscles/brain
Term
What are three ketone bodies?
Definition
acetone, acetoactone and beta-hydroxyburyrate
Term
What is acidosis caused by?
Definition
decrease in pH by accumulation of ketone bodies
Term
where are ketone bodies formed?
Definition
in the matrix of liver
mitochondria
Term
how many CoA are produced per ketone body?
Definition
3 CoA are released
Term
what enzyme does the liver lack which stops ketone metabolism?
Definition
β-ketoacyl-CoA transferase,also called
thiophorase,
Term
each Beta-hydroxybutyrate produces what when converted back?
Definition
2 Acetyl-CoA
Term
Why is HMG-lyase stored in the mito?
Definition
so it can not interfere with cholesterol synthesis
Term
What are the two main sites of protein degradation ?
Definition
lysosome and proteasome
Term
What kind of proteases are present in lysosome?
Definition
many cysteine proteases, as well as some
aspartate proteases and one zinc protease
Term
What kind of proteases are present in proteasome?
Definition
threonine proteases
Term
what hormone is used to release HCl and histamine?
Definition
Gastrin
Term
Chief cells secrete what?
Definition
pepsinogen, which auto cleaves and attacks protein
Term
What does secretin do in the small intestines?
Definition
causes the release of bicarbonate which neutralizes the acid
Term
What converts trypsinogen to trypsin?
Definition
enterpeptidase from the pancreas which si protected by pancreatic trypsin inhibitor
Term
what three forms can ammonia by transferred to liver as?
Definition
alanine. glutamine, glutamate
Term
What is the process of transamination?
Definition
transfer of Nitrogen to ketoglutaric
acid, ends in glutamate specific to donor.
Term
What is the prosthetic group for transamination?
Definition
Pyridoxal phosphate
Term
What is the process of deamination?
Definition
Glutamate Dehydrogenase acts on glutamate converting to ketoglutarate and releasing NH4, in mitochondria
Term
What do tissues use to convert NH4 into glutamine?
Definition
glutamine synthetase
Term
What enzyme does the liver use to convert back to glutamate? and NH4
Definition
glutaminase
Term
What is the positive reason to use alanine for a NH4 transporter?
Definition
removes extra pyruvate from muscles
Term
What happens in the glucose-alanine cycle?
Definition
glucose is shipped to muscles after alanine is broken down in liver to NH4 and pyruvate
Term
what are the three forms of nitrogen excretion ?
Definition
ammonia, urea, and uric acid
Term
Where do the two amino groups enter the urea cycle?
Definition
mito (ammonia (carbamoyl
phosphate)) and cytosol as aspartate
Term
What does carbamoyl phosphate synthetase I do?
Definition
produce carbamoyl phosphate, by combination of 2 ATP and 1 NH3
Term
How is Citrulline made?
Definition
combination of carbamoyl phosphate and ornithine, by ornithine transcarbamoylase
Term
What happens with Argininosuccinate synthetase?
Definition
citrulline combines with an asparate to create Argininosuccinate in a two step process
Term
Argininosuccinate is cleaved into?
Definition
cleaved by
argininosuccinase to arginine and
fumarate.
Term
Arginase cleaves? to?
Definition
arginine to urea
and ornithine, found only in liver.
Term
What is the aspartate-argininosuccinate shunt?
Definition
the connection between CAC and Urea cycle.
Term
What does N-acetylglutamate do?
Definition
allosteric
activator of carbamoyl phosphate
synthetase.
Term
What is the cost of Urea synthesis?
Definition
4 phosphates but after NADH reproduction only 1.5 ATP
Term
What two things are used to treat deficiencies in urea cycle enzymes?
Definition

Benzoate and phenylbutyrate

b/c they use up glycine and glutamine

Term
What two amino acids are only ketogenic?
Definition
lysine, leucine
Term
What is unique about tetrahydrofolate?
Definition
can transfer differing reduction forms of Carbon
Term
What three groups play a big role in amino acid catabolism?
Definition
Biotin, Tetrahydrofolate and S-adenosylmethionine
Term
Lack of phenylalanine hydroxylase leads to?
Definition
causes
defective neural development and
mental retardation. and PKU
Term
How to treat PKU
Definition
diet of PHe and Tyr. or supplement precursors
Term
What are the three pathways of glycine degradation?
Definition
convert to serine, Cleaved to CO2, NH4+ and a methylene or converted in kidney to oxalic acid by D-amino acid oxidase
group or
Term
Maple Syrup Urine Disease is?
Definition
defect in Branched
Chain α-keto Acid Dehydrogenase Complex. leads to alot of branched AA
Term
What enzyme performs oxidative phosphorylation on pyruvate?
Definition
Pyruvate dehydrogenase complex
Term
What do the 5 reactions of PDH do?
Definition
1.) decarboxylates 2.)oxidize to carboxylic acid 3.) acetyl group is transferred from lipoyl group to CoA 4.)reduced lipoate is oxidized to original form 5.)Hydrogens is transferred to NAD
Term
What is the effects of Beriberi?
Definition
loss of neural function do to poor PDH function
Term
What is the overall result of CAC?
Definition
3 NADH, 1 FADH2, 1 ATP(GTP) and 2 CO2
Term
What are the intermediates of CAC? (9)
Definition
1.)Acetyl-CoA and Oxaloacetate
2.) Citrate
3.) Isocitrate
4.) alpha-ketoglutarate
5.) Succinyl-CoA
6.)Succinate
7.) Fumarate
8.) Malate
9.) Oxaloacetate
Term
What is the process of citrate synthase?
Definition
OAA binds then opens the binding site for acetyl-CoA forms a thioester intermediate which is hydrolyzed
Term
How can aconitase proceed forward?
Definition
product (isocitrate) is used up immediately
Term
What is transferrin?
Definition
dietary iron carrier in blood, stored by ferritin
Term
What is the moonlighting effect of aconitase?
Definition
it triggers Iron Regulatory Protein 1,
which binds to Iron Response Elements up taking more Fe
Term
What does isocitrate dehydrogenase do?
Definition
produces NADH, CO2 and alpha-ketoglutarate
Term
What does α-Ketoglutarate Dehydrogenase Complex produce?
Definition
succinyl-CoA, NADH
Term
what does Succinyl-CoA Synthase do?
Definition
produce GTP/ATP and Succinate
Term
What does Succinate Dehydrogenase do?
Definition
Produces FADH2 and Fumarate
Term
what can compete with Succinate Dehydrogenase?
Definition
malonate
Term
What does Fumarate Hydratase or
Fumarase do?
Definition
malate
Term
Whats the products of Malate Dehydrogenase?
Definition
OAA and NADH
Term
How many cycles does the methyl Cardon of acetyl survive in CAC?
Definition
2 cycles
Term
When is the Carboxyl C of acetyl lost to CO2?
Definition
second cycle
Term
What activates the most important anaplerotic enzymes? and how is it regulated?
Definition
Pyruvate carboxylase activated by acetyl CoA
Term
what activates PEP carboxylase?
Definition
F1,6-BP,
which accumulates when CAC is slower than glycolysis.
Term
What are the two steps of biotin catalyzed reactions in pyruvate carboxylase?
Definition
1.) bicarbonate is converted to the more activated CO2
2.) CO2 reacts with pyruvate to form oxaloacetate
Term
where is CAC regulated?
Definition
PDH complex,
Citrate synthase,
Isocitrate DH, and
α-ketoglutarate DH
Term
what is the main regulator of PDH?
Definition
The Kinase is allosterically activated by ATP and it inacivates the E1 of PDH by phosphorylation
Term
What is the regulator of the first three steps of CAC?
Definition
products and ATP and Calcium for isocitrate DH/alpha-ketoglutarate DH
Term
What does excess citrate inhibit?
Definition
Phosphofruktokinase to slow down glycolysis that feeds CAC
Term
What enzyme is membrane bound in CAC?
Definition
Succinate DH
Term
what is the Glyoxylate cycle?
Definition
a circular pathway that takes in two molecules of acetate and put out one molecule of succinate (glyoxysome) starts with glyoxylate not OAA
Term
What three enzymes are present in both CAC and Glyoxylate Cycle?
Definition
Citrate synthase, aconitase, and
malate DH
Term
What are two unique enzymes to glyoxylate cycle ?
Definition
Isocitrate lyase and malate
synthase, essential for this cycle,
are absent in vertebrates
Term
What is the branching point of CAC/glyoxylate cycle?
Definition
isocitrate lyase regulated by kinase/phosphatase
Term
What does the kinase ability do to isocitrate DH?
Definition
shunts isocitrate to the
synthetic route to Glc via glyoxylate cycle
Term
Why does intermediates of CAC activate phosphatase ability?
Definition
to activate isocitrate DH (more CAC)
Term
What do AMP/ADP do to CAC?
Definition
inhibit the kinase which inhibits isocitrate DH
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