Lecture Citric Acid Cycle (Exam #3) Flashcards
TPP undergoes
oxidative decarboxylation
What in the active site of the PDH kinase adds the Pi?
Ser-OH
Acetyl CoA along with ________ is converted to _____
oxaloacetate; citrate
What is activated by acetyl CoA
pyruvate carboxylase
What is a reaction used to replenish CAC?
anaploretic reaction
Why is acetate and oxaloacetate joined together?
because the enzyme can only do alpha or beta cleavage
Acetyl CoA can be generated by break down of?
fatty acids and amino acids
Citrate Synthase
converts oxaloacetate & acetate to citrate
What type of mechanism does citrate synthase use?
ordered sequential mechanism
Describe the mechanism of citrate synthase? (5 steps)
OA binds first (CS closes) Acetyl CoA binds (CS closes more) Citryl CoA made (CoA with citrate) CoA released with water citrate is made
What is Citryl CoA? Is it stable?
CoA with citrate; NO
Why does citrate synthase close tighter and tighter?
because it doesn’t want to lose the acetate by letting H2O in
Citrate is converted to isocitrate via
aconitase
Isocitrate is converted to ______ via ______
alpha ketoglutarate (KG); isocitrate dehydrogenase
Isocitrate dehydrogenase
oxidative decarboxylation
undergoes alpha cleavage
irreversible
What make isocitrate dehydrogenase slow?go?
ATP/NAPH- slow
ADP/NAD+-go
How many turns of the CAC to remove acetate groups?
3
alpha ketoglutarate is similiar to ___ except it does not have kinase phosphase. It has all the other 3 catalytic enzymes.
PDH
Alpha KG is converted to _____. During this process, ____ is removed. The removal is_____
Succinyl CoA; CO2, spontaneous
______ converts succinyl CoA to succinate
succinyl CoA Synthase
Succinyl CoA Synthase is also known as
Thiokinase
What is used by thiokinase to break thioester bond?
inorganic phosphate
Where is ATP made?
in the muscle
Where is GTP made?
in the liver
What converts succinate to fumarate?
succinate dehydrogenase (SDH)
Succinate dehydrogenase is the only enzyme not in the matrix where is it embedded?specifically?
inner mitochondria membrane
Complex 2
Succinate Dehyrogenase produces____ along with fumarate?
FADH2
Fumarase uses ____ to replace double bond between carbons
water
Fumarase
converts fumarate to malic acid
What enzyme converts malic acid to oxaloacetate
malate dehydrogenase
Which enzymes are the regulatory enzymes in the CAC?
citrate synthase
isocitrate dehydrogenase
alpha ketoglurate dehydrogenase
What slows isocitrate dehydrogenase? (3)
ATP
NADH
citrate
What slows alpha ketoglumarate dehydrogenase? (3)
ATP
NADP
succinyl CoA
How many acetates go thru CAC?
2
How many CO2, NADH, FADH, and ATP are produced total after citric acid cycle?
CO2=4
NADH=6
FADH2=2
ATP=2
Both NADH and FADH2 produce______
ATP
Oxaloacetate can also be converted into which amino acid?via?
aspartic acid
transamination
The citrate produced creates what type of feedback on glycolysis?
negative feed back
What does dehydrogenase involve?
removal of hydrogen
Which molecules can be converted into amino acids
oxaloacetate
alpha ketoglutarate
Citrate Synthase has a _____ delta G
negative
Malate Dehydrogenase has a _____ delta G
positive; not favorable
Since MDH has a positive delta G, what enzyme helps the reaction occur
Citrate Synthase
