TCA cycle Flashcards
The pyruvate dehydrogenase complex converts pyruvate into
Acetyl CoA
the PDC requires cofactors to operate. What are they
Lipoic acid
Thiamin
CoA
Niacin
Riboflavin
The PDC requires 3 steps to convert pyruvate to acetyl CoA. What are they?
Decarboxylation
Oxidation
Transfer of acetyl group to CoA
Regeneration of active enzyme
The PDC is a __ subunit enzyme complex
3
In E1 of the PDC, which Reaction is catalyzed
Decarboxylation of pyruvate
In E2 of the PDC, which reaction is catalyzed
Transfer of acetyl group to CoA
In E3 of the PDC, what is catalyzed
Regeneration of Disulfide form of lipoate
PDH is active when it is________and inactive when__________
Dephosphorolated
Phosphorylated
PDH is regulated by which enzymes
PDH kinase
PDH phosphotase
PDH kinase is activated by
High ATP & acetyl CoA and NADH
PDC phosphotase is activated when
ATP and acetylene CoA is low
PDHC deficiency causes_________
Lactate buildup
Arsenic poisoning inhibits______resulting in impaired production of acetylene CoA and energy production via oxidative phosphorylation
A subunit of PDHC
Fatty acid oxidation inhibits PDCH because fatty acid oxidation forms a large amount of _________which would replace the amount formed in PDCH
Acetyl CoA (which already inhibits the complex)
In the first step of the TCA cycle, acetyl CoA binds with oxaloacetate to form________via_________
Citrate; citrate synthase
Citrate synthase requires ATP. T/F
False. Only a water molecule is needed
Citrate synthase is highly regulated. T/F
True
Citrate is isomerized to isocitrate via the enzyme
Aconitase
Isocitrate is dehydrogenated to alpha-ketoglutarate via the enzyme
Isocitrate dehydrogenase
The key regulatory enzymes of the TCA cycle is
Citrate synthase
Isocitrate dehydrogenase
Isocitrate is dehydrogenated to form________in the TCA cycle
Alpha-ketogluterate
This enzyme complex is similar to the PDHC which requires the same cofactors and has the same subunits
Alpha-ketoglutarate dehydrogenase complex
Alpha-ketoglutarate is formed into succinyl CoA via
Alpha-ketoglutarate dehydrogenase complex
Succinyl CoA is catalyzed by succinyl CoA synthetase to form __________and the cleavage of the CoA produces
Succinate;ATP/GTP
Succinate is catalyzed by succinate dehydrogenase to form
Fumarate
This is the only enzyme that is free floating and has physical contact with the ETC
Succinate dehydrogenase
Fumerate is converted into_________ via fumerase and water
Malate
Malate is catalyzed by malate dehydrogenase to for,
Oxaloacetate
This reaction in the TCA cycle is considered unfavourable
Malate ———->oxaloacetate
This reaction in the TCA cycle forms FADH2 from FAD+
Succinate to fumarate
CO2 leaves the cycle during these 2 reactions
Isocitrate to alpha ketoglutarate
Alpha ketoglutarate to succinyl,CoA
3 NADH are formed via these reactions in the TCA cycle
Isocitrate to alpha ketoglutarate
Alpha ketoglutarate to succinyl CoA
Malate to oxaloacetate
FADH2 is formed during this reaction
Succinate to fumarate
PDHC is slowed down by these substrates
ATP
Acetyl Coa\A
Fatty acids
NADH
Formation of acetyl CoA from pyruvate is accelerated by these substrates
AMP
CoA
NAD+
Ca 2+
Sythesis of citrate is inhibited by
NADH
Succinyl CoA
Citrate
ATP
Anaplerotic reactions are reactions which replenish intermediates in the TCA cycle.
Pyruvate and PEP (Phosphoenol pyruvate) can be carboxylated to form
Oxaloacetate
Anaplerotic reactions are reactions which replenish intermediates in the TCA cycle.
Pyruvate with the prescence of a malic enzyme can be formed into
Malate
Anaplerotic reactions are reactions which replenish intermediates in the TCA cycle.
Glutamate can be formed into
Alpha ketoglutarate
Pyruvate carboxylase can convert pyruvate to oxaloacetate with______as a cofactor
Biotin
This intermediate of the TCA cycle can be converted into glucose in the liver during the fasting state
Malate
These intermediates of the TCA cycle can be converted into amino acids
Oxaloacetate
Alpha ketoglutarate
Pyruvate carboxylase are primarily found in the___________ and is activated by
Liver, brain, and adipose tissue; acetyl CoA
Pyruvate carboxylase deficiency leads to_______and causes
Lactic acid build up; hypotonia , delayed movement, ataxia
