Carbohydrate metabolism 2 Flashcards
Overview of glucose oxidation
1) glucose
2) glucose-6P
3) triose-P
4) pyruvate
5) lactate
Which is the only reversible reaction in glucose oxidation
Pyruvate to lactate
Where does glycolysis occur
Cytosol
Where does oxidation occur
Mitochondrial matrix
What happens to pyruvate in oxidation
- can become lactate
- Goes to become acetylcoa which feeds into the TCA cycle
What is the purpose of the TCA cycle
Energy production
What does the TCA cycle prduce
- removal of pairs of electrons to form NADH and H+ and FADH2 from NAD+ AND FAD+
- biosynthesis of metabolites
What does pyruvate dehydrogenase do
Turn pyruvate into acetyl CoA
Reaction of pyruvate to acetyl CoA
Pyruvate + NAD+ + CoA—>
Acetyl CoA+ NADH +CO2
Why is the pyruvate dehydrogenase reaction important
- commits pyruvate to TCA cycle
- Controls the entry of glucose to TCA cycle
- RATE LIMITING STEP
- irreversible
- regulated
How is the pyruvate dehydrogenase reaction regulated
- allosterically
- covalently
- hormonally (insulin activates)
How many enzyme activities are there of PDH
3
What are the enzyme activities of PDH
E1
E2
E3
5 coenzymes of PDH
Thiamine LIpoamine CoA FAD+ NAD+
what is the inactive form of PDH
PHosphprylated
