Oxidative
Decarboxylation of
Pyruvate & Krebs Cycle
Dr. Endriyas Kelta (DMD, MSc)
Assistant Professor, AAU
1
,Citric Acid Cycle
– Also known as:
• Tricarboxylic acid (TCA ) cycle
– After its substrates, Citrate &
Iso-citrate
• Krebs cycle
– (After its discoverer, Hans Krebs)
– Special metabolic pathway which runs in
mitochondria
• Most of our cells contain mitochondria which act
as “mobile power plant”
• Few cells however, don’t have mitochondria
– E.g., Red Blood cells (do not run Krebs’ cycle )
• All the enzymes which mediate the cycle
present within mitochondria 2
, Cont…
Mitochondria:
– Intracellular organelles which are bounded by
double membranes
• Outer membrane
• Inner membrane
– What was origin of mitochondria?
• Originally, mitochondria were energy producing
bacteria
• Millions’ of years back, visited eukaryotic cell
– Eukaryotic cell provided protection & nutrition to
mitochondria
– Bacteria were very happy & provided energy
– What is proof that mitochondria were bacteria?
• Like bacterial DNA, mitochondrial DNA is circular
3
, Cont…
– Inter-membraneous space
– Matrix
• All the substances in the inner side of inner membrane
– What are substances present in the mitochondrial
matrix?
» Mitochondrial DNA
» Mitochondrial RNA
» Mitochondrial Ribosomes
» Krebs cycle enzyme
» Pyruvate dehaydrogenase complex
» FA beta oxidation enzymes
4
Decarboxylation of
Pyruvate & Krebs Cycle
Dr. Endriyas Kelta (DMD, MSc)
Assistant Professor, AAU
1
,Citric Acid Cycle
– Also known as:
• Tricarboxylic acid (TCA ) cycle
– After its substrates, Citrate &
Iso-citrate
• Krebs cycle
– (After its discoverer, Hans Krebs)
– Special metabolic pathway which runs in
mitochondria
• Most of our cells contain mitochondria which act
as “mobile power plant”
• Few cells however, don’t have mitochondria
– E.g., Red Blood cells (do not run Krebs’ cycle )
• All the enzymes which mediate the cycle
present within mitochondria 2
, Cont…
Mitochondria:
– Intracellular organelles which are bounded by
double membranes
• Outer membrane
• Inner membrane
– What was origin of mitochondria?
• Originally, mitochondria were energy producing
bacteria
• Millions’ of years back, visited eukaryotic cell
– Eukaryotic cell provided protection & nutrition to
mitochondria
– Bacteria were very happy & provided energy
– What is proof that mitochondria were bacteria?
• Like bacterial DNA, mitochondrial DNA is circular
3
, Cont…
– Inter-membraneous space
– Matrix
• All the substances in the inner side of inner membrane
– What are substances present in the mitochondrial
matrix?
» Mitochondrial DNA
» Mitochondrial RNA
» Mitochondrial Ribosomes
» Krebs cycle enzyme
» Pyruvate dehaydrogenase complex
» FA beta oxidation enzymes
4
