lipid and amino acid metabolism Flashcards
acyl vs acetyl vs acetone
RC=OR
CH3C=OR
CH3C=OR
what is the need of shuttles
molecules such as NADH and acylCoA are not permeable to the mitochondrial membrane
the principle of. a shuttle
AB+C –> A + BC
BC cross
BC + A1 –? A1B + C
C cross back
2 types of shuttle to transport NADH into the mitochondria from the cytosol
AM and GP
AM = when I wake up = aspartate malate
GP= glycerol3 phosphate
aspartate malate shuttle
aspartate - NH2---- transamination ------> oxacloacetate NADH splits and donates H- oxaloacetate + H- ---->malate malate crosses cycle in revers aspartate returns to cytosol
purpose of aspartate in the AM shuttle
make oxaloactate by transamination as this is what taks electron energy from NADH
difference between AA shuttle and FA shuttle in B oxidation
in AA only H- adds on
in Beta OX the whole Acyl group adds onto the carrier
for what is aspartate malate shuttle
AA degradation
for what is carnitate shuttle
ONLY B oxidation
what is b oxidation
fancy way of saying catabolysing lipids
how to make oxaloacetate
DEaminate aspartate
difference between AM and GP shuttle
AM shuttle is more efficient because it produces 1 NADH which corresponds to 3ATP
GP shuttle is less efficient because it produces 1 FADH2 which corresponds to 2ATP
Number of main reactants in AM and GP shuttle
not including NADH
AM - 3
GP - 2
describe Glycerol 3 phosphate shuttle
dihydroxyacetone +H- = G3P
G3P cross
G3P= Dihydroxyacetone + H-
H-+ NAD+= NADH
what is the reaction when H- energy is stored on G3P
dihydroxyacetone phosphate ->glycerol 3 phosphate
why are they called the GP and aspartate MALATE shuttle
the GP and MALATE cross the mitochondrial membrane
what is more efficient AM or GP
AM because NADH is produced
which organs/tissues use AM shuttle
BS!
Brain and skeletal muscle
2 most energy consuming regions of body should have most efficient shuttle
which organs/tissues use GP shuttle
rest of body
lipid catabolism synonym
B oxidation
B oxidation overview
fatty acid +AcetylcoA–>AcylCoA
CARNITATE SHUTTLE
B oxidation cycle
CARNITATE SHUTTLE
AcylCoA + carnitate =>acylcarnitate
acylcarnitate => carnitate + acyl
acyl + coA2 => AcylCoA
what happens to AcylcoA if B oxidation does not occur
ketone body formation
what determines if ketone bodies formed from AcylcoA or if they enter the TCA cycle?
fat carb balance
calculate no ATPs from respiration at glycolysis
2ATP
1 NADHx2 =6ATP
calculate no ATPs from respiration at link
1NADH x2 = 4 ATP
calculate no ATPs from respiration at Krebs
3 NADH x2= 12ATP
1 FADH2 x2= 4 ATP
1 GTP x2= 2 ATP
no NADH made in krebs
3
no FADH2made in krebs
1
no reduced coenzymes made in Krebs
4 - double the number of CO2 release
how many compounds can the AA be metabolised to?
7
transamination reaction type
group transfer
transamination general description
NH2 passes from AA to ketoacid. This forms a new veto acid and AA acid due to recombination
what does NH2 replace in ketoacid?
O double bonded to the C
what does NH2 leave in AA
O double bonded to the C
regenerate NAD+ for glycolsys
1 make ethanol/lacte
2. AM/GP shutttle
how to get NAD+ for TCA
oxidative phosphorylation
conversion of dihydroxiacetaone to glycerol 3 phosphate
additionH-
what type of reaction is in both of the shuttle reactions
redox
what type of reaction is unique to which shuttle reaction
transamination of aspartate in AM shuttle
which membrane can the acyl carnitate cross?
mitochondrial membrane
type of reaction in carnitate shuttle
group transfer
how to remeber carnitate
carne
products of beta oxidation cycle
acetyl co A - enter TCA
reduced coenzymes
apart from AcetylcoA,what does beta oxidation produce?
reduced coenzymes
reduced coenzymes produced in B oxidation
FADH2 and NADH
number of enzymes in lipid synthesis
2
where does lipogenisis occur
liver or adipose tissue
where does lipogenisis occur
liver or adipose tissue in cytosol
carrier in lipogenisis
ACP ( a cows prick) ( acyl carrier protein)
the growing acyl chain is attached to this
coenzyme in lipogensis
NADPH (like in plants wtf)
what does lipogenisis start with?
acetyl co a
lipogensis basic pathway
Acetyl co A + COO-
Malate co A
Palmiatte
DENOVO Meaning
new
what elongates acyl chain on ACP
fatty acid synthase
lipogensis basic idea
acetylcoA –> malatecoA–> fatty acylACP–> fatty acid
hydrogenation, dehydration, carboxylation
what is invested at the start of B oxidation
2 x ATP
why is ATP invested in Beta oxidation
to join acetycoa to fatty acid
be wary when calculating B oxidation ATP released
2 initial ATP invested so -2
family of enzymes catalysing first oxidation step in fatty acid oxidation
acylcoa dehydrogenases
what does lipogenisis form
oxidised coenzyme, long acyl protein on ACP which gives rise to fatty acid
carrier in B ox
coA
what is a carrier
a shunt that moves molecules around
what joins a COO- acetylcoa
acetylcoa carboxylase
box vs lipogensis
AcoA vs ACP
hydration vs dehydration
decarboxylation vs carboxylation
what happens in Box cycle
the acylcoA is continually hydrated, dehydrogenated and 2 C are removed to form acetylcoA. The remnant acylco A merges with another incoming fatty acyl co a
transamination in AAM shuttle
GOAA
what catalyses joining of malate com and AcoA
Acetyl CoA carboxylase
what does acetylcoa malatecoa and palmitate pathway lead to making?
fatty acid
what is palmitate
a common fatty acid in lipogenesis pathway
how does AcoA enter cytosol from mitochondrial matrix
AcetylcoA cannot cross
temporarily forms citrate to cross membrane
what is the enzyme in the first step of beta oxidarion
acylco a dehydrogenase
what does beta ketothiolase do
in b oxidation cuts off the acetyl co a from the acyl co a
what does carnitine acyl transferase do
catalyses acyl addition and removal in the carnitine shuttle
when do ketone bodies occur
fasting, keto diet, starvation - low carbs
why do ketone bodies occur
the acetylcoa has to combine with oxaloacetate, form citrate to form citrate to enter TCA
fewer carbs means less oxaloacetate, so less AcetylcoA can enter the TCA cycle
ketone bodies are formed from AcetylcoA instead as an alternative way of harvesting energy
what precedes a ketone body
acetylcoa at end of beta oxidation cycle
who smells like ketone bodies
those with lots of diabetes
KETOGENSIS
make ketones
WHAT ARE Ketone bodies
alternative energy sources for body
where does lipogenisis occur
cytoplasm
where does B oxidation occur
in the mitochondria !! remember carnitine shuttle!
where does lipogenisis occur
cytoplasm
the 2 fates of acetylcoa after beta oxidation
TCA or ketones
how many bonds are broken from a fatty acyl co a if 8 acetyl are made
7
how many bonds are broken from a fatty acyl co a if 7 of each reduced coenzyme are made
7
how does AcetylcoA enter lipogenisis
combines to form citrate temporarily then exits mitochondrial membrane into cytoplasm
where are ketone bodies normally formed
liver mitochobdria
ketone body formation
little carbs - high glucagon - lipolysis - too may fa in blood - too much acoa and too little oxaloacetate
where does lipogensisi occur
liver or adipose tissue
normal cells vs cancer in fatty acid synthesis
in adults only fat cells or liver cells can synthesise fatty acids
in cancer cells all can synthesise fatty acids
2 b oxidation deficinecy
MCADD or carnitate deficiency
MCADD
medium chain acylcoa dehydrogenase deficiency
the enzyme used for cutting off 2C off the acylcoa is too little. therefore can only get little of energy of fattty acid
carnitate deficiency
not enough carnitate so fatty acyl group cannot enter the mitochondria
which enzyme forms malate cow in fatty acid synthesis
acetylcoacarboxylase
amino acid metabolism overview (2)
1 transamination 2 pyruvate formed 3 enter link or 1 deamination 2 NH2 becomes NH4 becomes urea 3 remainder ???
how can you target cancer cells given that they can all synthesise fatty acids
attack acetylcoadehydrogenase or fatty acid synthase
WHERE DOES deamination occur
liver
