Glycolysis II Flashcards
What are the last five intermediates of glycolysis?
- 1,3-bisphosphoglycerate
- 3-phosphoglycerate
- Phosphoglycerate
- Phosphoenolpyruvate
- Pyruvate
The last five steps of glycolysis are sometimes called the “_________________ _____________” phase.
Energy payoff
The sixth step of glycolysis converts glyceraldehyde-3-phosphate to ________________________________________________ via __________ __________________________________.
1,3-bisphosphoglycerate
GAP dehydrogenase
What is the mechanism for GAP dehydrogenase?
Redox reaction
As a redox reaction, step 6 of glycolysis requires what cofactor?
NAD+
What amino acid residue acts as a nucleophile in GAP dehydrogenase?
Cysteine
What is the enzyme that catalyzes the formation of 1,3-bisphosphoglycerate from glyceraldehyde-3-phosphate?
GAP dehydrogenase
What is the mechanism for glyceraldehyde-3-phosphate (GAP) dehydrogenase?
- The cysteine residue in the enzyme acts as a nucleophile and attacks the carbonyl carbon at C1
- This attack ultimately kicks out a hydride, which then attacks the NAD+ molecule
- The enzyme is covalently bound to the molecule; an inorganic phosphate attacks the carbonyl carbon at C1, expelling the enzyme
- 1,3-bisphosphoglycerate is formed
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In addition to being a redox reaction, the sixth step of glycolysis - the formation of 1,3BPG - also involves what type of catalysis?
Covalent catalysis
The sixth step of glycolysis requires the cofactor NAD+ and what other molecule to form 1,3-bisphosphoglycerate from glyceraldehyde-3-phosphate?
Inorganic phosphate
What is the seventh step of glycolysis?
The formation of 3-phosphoglycerate from 1,3-bisphosphoglycerate via phosphoglycerate kinase
Is the sixth step of glycolysis reversible?
Yes
- The cysteine residue in the enzyme acts as a nucleophile, attacking the C1 of carbonyl and expelling inorganic phosphate
- The lone pair of electrons on the nitrogen atom in NADH move and expel a hydride ion, which attacks the enzyme-transition state intermediate carbonyl and ultimately “kicks out” the enzyme
- Glyceraldehyde-3-phosphate has been reformed
![](https://s3.amazonaws.com/brainscape-prod/system/cm/300/455/382/a_image_thumb.jpg?1580243558)
What position does glyceraldehyde-3-phosphate dehydrogenase prefer on NADH: the proR or the proS?
ProS
What enzyme catalyzes the seventh step of glycolysis - the formation of 3-phosphoglycerate from 1,3-bisphosphoglycerate?
Phosphoglycerate kinase
What type of phosphorylation does the seventh step of glycolysis catalyze?
Substrate-level phosphorylation of ADP to ATP
What is the mechanism of phosphoglycerate kinase?
Phosphoryl transfer - nucleophilic attack of the acyl phosphate on 1,3-bisphosphoglycerate by the oxygen atom on ADP’s beta phosphate group
![](https://s3.amazonaws.com/brainscape-prod/system/cm/300/456/682/a_image_thumb.jpg?1580336587)
Phosphoglycerate kinase is named for its reverse direction. What is the mechanism for the reverse?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/300/575/853/a_image_thumb.jpg?1580336678)
The eighth step of glycolysis converts 3-phosphoglycerate to 2-phosphoglycerate. What enzyme catalyzes this reaction?
Phosphoglycerate mutase
Phosphoglycerate mutase requires a phosphorylated amino acid residue in its active site to function. What amino acid residue is it?
Histidine