Lecture 10.20.14 (Exam #3) Flashcards
What are the 2 concepts of glycolysis?
- preparatory stage: energy consumption phase (use ATP)
2. energy output phase (ATP made)
Enzyme used in Step 1 of glycolysis?
hexokinase
Characteristics of Hexokinase
big conformational change when substrate bound
G6P can act as product inhibitor
ATP allosteric effector
ATP _______ hexokinase
slow (T)
ADP/AMP _______ hexokinase
go (R)
In a reversible reaction….
the energy of the products and reactants are about the same; the concentration determines the direction
In an irreversible reaction….
products are more favored/ stable
exothermic reaction
How many metabolically irreversible reactions are in glycolysis?
3
Hexokinase (2)
converts glucose to G6P
use ATP
Enzyme used in Step 2 of glycolysis?
phosphoglucose isomerase
Phosphoglucose isomerase (PGI) (2)
converts G6P to F6P
important for step 4
Enzyme used in Step 3 of glycolysis?
phosphofructose kinase (PFK)
Phosphofructose Kinase (PFK 1) (3)
converts F6P to F16BP
use ATP
PFK 1 is a ______ step and ______ _____ step
committing step/ rate limiting
Where does ATP bind to trap enzyme in T state?
regulatory site
Where can ATP bind?
active site (small Km) or regulatory site (big Km)
What happens when the pH decreases?
ATP is more sensitive to regulatory region
PFK2
converts F6P to F26BP
Fructose Bisphosphate
converts F26BP to F6P
When is PFK1 able to work?
when F26BP is bound to the regulatory site
Enzyme used in Step 4 of glycolysis?
aldolase
Aldolase
converts F16BP to GAP and DHAP
Carbons in DHAP and GAP?
C3-4 are C1 & 2 of DHAP and GAP (add carbons)
Enzyme used in Step 5 of glycolysis?
TIM or TPI
TIM
converts DHAP to GAP (vice versa)
catalytically perfect
TIM prefers to turn ______ to _____
GAP to DHAP
TIM: Glutamic Acid acts as a___ while His acts as a _____
base; acid
