• 2 CO2
• one CoA
• 3 NADH's
• one GTP
• one FADH2

Describe step one of TCA

• OAA and acetyl CoA combine to produce    CoA-SH and citrate
• enzyme is citrate synthase

• citrate will be isomerized to aconitate via loss of water
• water is eventually lost, producing isocitrate
• via aconitase

• isocitrate oxidatively decarboxylated to alpha ketoglutarate
  • reduce NAD to NADH
  • eliminate CO2 from isocitrate
• via isocitrate dehydrogenase

• oxidative decarboxylation of alpha keto glutarate produce succinyl CoA
• Process
  • via alpha KG decarboxylase (TPP coenzyme), produce CO2
  • remains react with CoA-SH and via transsuccinylase (coenzyme is lipoic acid), produce succinyl-CoA
  • via dihydrolipolyl DH (coenzyme FAD), produce NADH
• enzyme complex is alpha KG DH

• tranfer of high energy bond
• succinyl CoA combines with GDP/P to produce CoA-SH and succinate
• enzyme is succinyl-CoA synthetase (if reverse, succinate thiokinase)

• succinate oxidized to produce FpH2 and fumarate
• via succinate dehydrogenase/complex II

• hydration of fumarate
• fumarate combines with water to form malate
• enzyme is fumarase

Step 8 of TCA

• oxidation of malate fo form OAA and NADH (couple with reduction of NAD)
• via enzyme malate dehydrogenase

• coupled to oxidative phosphorylation 
• we need NAD to run TCA cycle
• in ETC, NAD's are generated and the remaining H's run through complex V to generate ATP
• if the ETC slows down, the NADH/NAD ratio will be high
• this causes a slowing of TCA

• glutamate, which could be converted to
  • AA's
  • purines/pyrimidines

• converted to FA's
  • TAG
  • phospholipids
• converted to cholesterol
  • hormones
  • bile salts

Other fates of succinyl CoA

• can be converted to heme
• can be produced from propionyl CoA

Other fates of OAA

• convert to Asp
  • Asn
  • purine/pyrimidine
• convert to PEP, which goes to glucose

use Phe, convert to Tyr, than to fumarate and oxaloacetate

Mechanism of synthesis of OAA

• from pyruvate and CO2, produce OAA
• via pyruvate carboxylase with biotin as coenzyme
• CO2 binds to biotin and ATP is hydrolyzed

• in liver and kidney of mitochondria
• increase acetyl CoA leads to increase activity of pyruvate decarboxylate

Relation between acetate and ATP level

• glucose via glycolysis
• FA via beta oxidation
• ethanol via alcohol fermentation
• ketone bodies
• ketogenic AA's (Lys, Leu)