Biochemistry-Glycolysis II Flashcards
Glycolysis step 1.
This is irreversible and traps Gluc-6-P in cell because GLUT transporters do not recognize Gluc-6-P.
Glycolysis step 2.
Carbonyl group on 1st carbonyl is moved to 2nd carbon in aldose-ketose isomerase reaction.
Glycolysis steps 3, 4 and 5.
1st carbon of Fru-6-P is irreversibly phosphorylated. The structure of Fru-6-P is ripe for an alpha-beta cleavage near the carbonyl and cleavage yields 2 trioses. Then an aldose-ketose isomerization occurs to make the trioses equivalent.
Why is the carbonyl group moved to position 2 by phosphoglucoisomerase?
If it were not moved, cleavage of glucose would yield 2 and 4 carbon fragments.
What enzyme is the most committing enzyme to glycolysis?
PFK-1
Glycolysis step 7.
Creates an extremely high energy molecule in preparation to form an ATP from an ADP. Note the enzyme is named for the reverse reaction.
Glyceraldehyde-3-phosphate dehydrogenase mechanism.
Thiohemiactal forms and NAD oxidizes it to a thioester. This creates a high energy bond. Inorganic phosphate attacks the thioester and breaks one high energy bond to form another.
Glycolysis step 9
Dehydration to form a double bond
Glycolysis step 10.
Highest energy phosphoenolpyruvate synthesizes ATP from ADP irreversibly.
Pyruvate kinase mechanism
Enol pyruvate is extremely unstable. When phosphoenolpyruvate’s phosphate is transferred to form ATP. It tautomerizes to pyruvate.
What are the irreversible steps in glycolysis?
1,3 and 10 (Hexokinase, PFK-1 and pyruvate kinase)
What does aerobic glycolysis yield?
2 NADH, 2 ATP and 2 Pyruvate
What does anaerobic glycolysis yield?
2 ATP and 2 Lactate. NADH is not formed because it is recycled to NAD when Pyruvate goes to lactate.
What are some significant carrier in the inner mitochondrial membrane?
Malate, aspartate, glutamate, alpha-ketoglutarate, pyruvate etc.
Glycolysis step 6
Glycolysis step 8
Big picture of glycolysis
What 3 transporters are absent in the inner mitochondrial membrane?
