Acetyl CoA and CAC Flashcards
What is Acetyl-CoA made of
acetate and coenzyme A linked by thioester bond
what is Aoenzyme A made of
AMP
vita B5
mercaptoethylamine
succinyl COA
metabolic intermeidate of CAC
fatty acyl COA
derivative acylated with a fatty acid
what is the unacylated form of Coenzyme called
CoASH
What can acetyl-CoA be formed from
Cars
fatty acids
amino acids
what can acetyl-CoA serve as
substrate of CAC
metabolic precursor for fatty acids, ketone bodies, cholesteral
how does glycose get to acetyl CoA
glycolysis to pyruvate which undergoes oxidative decarboxylation
how do free fatty acids become acetyl CoA
beta oxidation
how do amino acids become acetyl CoA
demaination and oxidation
what is the major source of pyruvate
glycolytic pathway
Is the PDH complex reversible
no
What are the 3 enzymes of the PDH complex
pyruvate decarboylase
dihydrolipoyl transacetylase
dihydrolipoyldehydrogenase
first step of PDH complex
pyruvate decarboicated to form hydroexyethyl derivative bound to TPP
second step of PDH complex
hydroxyethyl intermediate oxidated to acetyl group by transfer of disulfide form of lipoic acid bound to dihydrolipoyl transcetylase
3rd step of PDH complex
acetyl group trransfered to CoASH by transacetylase
4th step of PDH complex
regen lipoic acid via dihydrolipoyl dehydrogenase
5th step of PDH compelx
FAD2 reoxidated to FAD by dihydrolipoyl dehydrogenase. produces NADH
waht are the products of PDH complex
Acetyl CoA, CO2, NADH, H+
What is TPPP
pyrophosphorylated form of thiamin
Where is the PDH complex
mitochondrial matrix
where is pyruvate generated
cytosol
What is the general reaction of PDH compelx
pyrucate is converted to acetyl-CoA via loss of DO2
what happens to the NADH in PDH complex
oxidized by ETS, resulting in generation of 3 ATPs
what are teh 5 coenzymes of PDH complex reaction
CoA, NAD+, TPP, lipoamide, FAD
what are the 2 soluble coenzymes of PDH complex reaction
CoA, NAD+
what are the 3 tightly bound coenzyme of PDH compelx
TPP, lipoamide, FAD
What are the 4 B vitamins in coenzyme strucutres
thiamine, riboflavin, niacin, pantothetnic acid
waht is thiamin assocaited with
TPP
what is riboflavian associated with
FAD
what is niacin assoicated with
NAD/NADH
what is pantothenic acid assocaited with
CoASH
what happens if you get inhibition of PDH comples
metabolic acidosis
roles of CAC
major ATP generating pathway
metabolic precursors for biosyntehsis
where does the CAC take place
mitochondria
Waht does the CAC generate
3 NADH, 1 FADH2, 1 GTP
how many ATPs can the CAC generate
12
1st reaction in CAC
acetyl CoA + OAA –> citrate via citrate synthase
2nd reaction in CAC
citrate –> isocritrate via acontiase
3rd reaction in CAC
isocitrate –> alpha ketoglutarate via isocitrate dehydrogenase
4th reaction in CAC
alpha KG —> succinyl-CoA via alpha KG dehydrogase complex
5th reaction in CAC
succinyl CoA —> succinate via succinyl-CoA synthetase
6th reaction in CAC
succinate —> fumrate via succinate dehydrogenase
7th reaction in CAC
fumate —-> malate via fumarase
8th reaction in CAC
malate —> OAA via malate dehydrogase
what CAC reactions produce CO2
isocitrate —-> alpha-KG
alpha-KG —-> succinyl-CoA
what CAC reactions produce NADH
isocitrate —> alpha-KG
alpha KG —-> succinyl CoA
malate —> OAA
what CAC reaction produces FADH2
succinate —> fumarate
how many ATPs does NADH yield
3
how many ATPs does FADH2 yield
2
how many ATPs can be formed from each molecules of pyruvate
15
how many ATPs can be formed from each glucose molecule
30
what happens if oxygen in limited
pyruvate gets reduced to lactate using NADH
what does citrate lead to
Acetyl-CoA, fatty acids, sterols
waht does alpha-KG lead to
glutamate, amino acids purine
what does succinyl-CoA lead to
porphyrins
what does malate lead to
pyrucate alanin
what os OAA lead to
phosphoneyl pyruvate, glucose
aspartate, amino acids, urea, purines, pyrimdiens
what is the most important anaplerotic enzyme
pyruvate carboxylase
what does pyruvate carboxylase do
turn pyruvate into OAA,
where is pyruvate caroxylase
mitochondrial matrix
what does pyruvate carboxylase requrie
biotin
function of glutamate dehydrogenase
remove amin group from amino acids so they can be oxidized to form ATP
what are the key intermediates that signal there is a lot of energy
acetyl-COA
citrate
NADH
what inhibit the PDH Complex
acetyl CoA, NADH, ATP, fatty acids
what stimulates the PDH complex
CoASh, pyrucate, ,NAD+, ADP
how does phosphorylation state affect activity of PDH complex
less active in phosphoryaltes state
what happens when PDH protein kinase is activated
inhibits PDH activity
what are the 2 most important enzymes for regulation of CAC
isocitrate dehydrogenase, alpha-KG dehyrogenase complex
what is isocitrate dehydrogenase activated by
ADP
what is isocitrate dehydrogenase inhibited by
NADH
what is alpha-KG dehydrogenase inhibited by
succinyl-CoA and NADH
symptoms of thiamin defiency
mental confusion
ataxia
loss of eye coordination
symptoms of beri beri
neuromuscluar symptom
muscle atrophy
weakness