KREBS CYCLE Flashcards
It is the final common pathway bec all biomolecules can enter
Krebs cycle
Other term for krebs cycle
Citric acid cycle
tricarboxylic acid
Where krebs cycle is located
Mitochondrial matrix
Three enzymes used to produce acetyl coA
Pyruvate dehydrogenase complex
During glycolysis,glucose is converted into
PYRUVATE
Pyruvate undergoes removal of carboxyl grp
Oxidative decarboxylation
Coenzymes used to produce acetyl coA
NAD FAD CoA SH NADH Lipoate TPP thymine pyro phosphate
Formation of NADH and FADH2 is catalyzed by
Dihydrolipoyl dehydrogenase
E1
Pyruvate dehydrogenase
E2
Dihydrolipoyl transacetylase
E3
Dihydrolipoyl dehydrogenase
Step 1:
Acetyl coA + _______ = Citrate
Enzyme used:
Oxaloacetate
Citrate synthase
Step 2: Citrate ➡️ Isocitrate
What enzyme?
Aconitase
This step shows you
rearrangement of func group or isomerization
reversible
Step 2: formation of isocitrate
Step that shows generation of NADH
3 oxidation of isocitrate to a-KT & CO2
4 oxidation of a-KT to succinyl coA and CO2
8 oxidation of malate to oxaloacetate
Irreversible
NAD ➡️ NADH
NADP ➡️ NADPH
- Oxidation of a-KT & Co2
Enzyme in step 3/ oxidation of a-KT & Co2
Isocitrate dehydrogenase
Enzyme in formation of citrate
Step 1
Citrate synthase
Enzyme in formation of isocitrate
Step 2
Aconitase
Carries 3 mol
NADH
Steps that shows:
Generation of NADH
Irreversible
Oxidation & decarboxylation
Step 3: oxidation of isocitrate to a-KT & Co2
Step 4: oxidation of a-KT to succinyl coA & Co2
Enzyme in step 4/ oxidation of a-KT to succinyl coA & co2
A-ketoglutarate dehydrogenase complex
High energy compound
Reactive product of the reaction
GDP
Step 5: Reactant: Enzyme: Product: Production of....
Conversion of succinyl coA to succinate Reactant: Succinyl coA Enzyme: succinyl coA synthetase or thiokinase Product: succinate GDP*
This step demonstrates SUBSTRATE LEVEL OF PHOSPHORYLATION
Step 5
Conversion of succinyl coA to succinate
Charac of step 5–
Forms atp/ gtp without entering electron transport chain
Substrate level of phosphorylation
Step 6:
Enzyme:
Formation of ___
Oxidation of succinate to fumarate
Succinate DEhydrogenase
FADH2
Step 7:
Enzyme:
Hydration of fumarate to malate
Enzyme: fumarase
Step 8:
Emzyme:
Oxidation of malate to oxaloacetate
Malate dehydrogenase
Products formed in krebs cycle
3 NADH
GDP
FADH2
of atp..
NADH
GDP
FADH2
N-3
F-2
G-1
How many atp based on 1 mol of acetyl coa
12 atp
Enzyme in substrate level of phosphorylation
Succinyl coA synthetase
Irreversible steps and enzymes..
- Formation of citrate - citrate synthase
- Oxidation of isocitrate to a-KT & co2
- Oxidation of a- KT to succinate & co2 - a ketoglutarate dehydrogenase complex
Reversible reaction
Serves as replenishment for Krebs cycle
Anaplerotic reaction
Product formed in anaplerotic rxn
Oxaloacetate
Rate limiting enzymes that catalyze rate limiting steps
Citrate synthetase
Isocitrate dehydrogenase
A ketoglutarate dehydrogenase complex
step ➡️ FADH2
Step 6
Oxidation of succinate to fumarate
Step ➡️ GDP
Step 5
Conversion of succinyl coA to succinate