PGK catalyzes 1st S-lvl +P

Question 1

PGK structure

Answer 1

phosphoglycerate kinase, ONLY monomeric enzyme in glycolysis

Has two domains that are joined by a hinge. Each domain binds a substrate. One binds 1,3BPG, the other binds mg-ADP/ATP.

When both substrates are bound, the hinge closes.

Question 2

PGK prefers which conformation

Answer 2

prefers the open conformation, so must utilize a conformation selection with a pop shift to favor the closed.
open: doesnt do catalysis. However, it is more stable because the hydrophobic patches are smaller/less exposed which makes the enzyme more stable. The closed conf must be stabilized by binding BOTH substrates (1,3,BPG and mg-ADP/ATP)

Question 3

How is le-chat involved?

Answer 3

when closed in stabilized, shifting the equilibrium.

Question 4

What organic chem rxns and phosphate groups are involved in this reacction?

Answer 4

SN2-like reaction:

Question 5

Attacking phosphate

Answer 5

Sn2 like

Question 6

using a Phos O to attack something else

Answer 6

NAS

Question 7

Why did GAPDH make GAP into 1,3BPG

Answer 7

we were saving ∆G from its mechanism to use it to synthesize ATP (substrate level Phosphorylation of ADP by PGK)