Chapter 15 Flashcards
Malate Asparatate system
NADH can’t cross, so malate does and enters cytosol
Can be dehydrogenated to oxaloacetate once across, which generates NADH
Oxaloacetate transanimated to aspartate which crosses back
Overall, 2 e- carried
What can take 1 or 2 e-?
What has to take 1?
What has to take 2?
Ubiquinol: 1 or 2
FADH/NADH: 2
cyt. c: 1
What can citrate transport be used for?
Getting Acetyl-CoA into cytosol for fatty acid synthesis
What protein imports ADP into matrix and exports ADP to IMS?
Adenine nucleotide translocase
How does mitochondria bring Pi into matrix?
Via H+ symporter
What Ubiquinol Pool does
Shuttles e- from cytosolic NADH to Q, bypass complex 1
Complex 1 path
NADH dehydrogenase (oxioreductase)
1) NADH –> NAD+, gives 2e-
2) FMN –> Fe-S center
3) –> Ubiquinone in C1 arm
Complex 2 enzyme
Succinate dehydrogenase
(Acetyl-CoA dehydrogenase, mitochondria dehydrogenase)
Makes QH2
Complex 3
Cytochrome b/C1 complex
Integral membrane protein 2e- –> Cyto C
ISP –> Cyto. C (functional core)
2nd e- on each round goes to cyt. b which regenerates QH2
Fe Heme group reduced
Complex 4
Cyt. C oxidized (– >Fe 3+)
1) Cu redox center (CuA)
2) Fe-Cu center (Heme) where O2 reduced - binuclear center
3) 0.5 O2 + 2H+ –> H2O
What makes up F0
alpha, 2x beta, c ring
What makes up F1
3x alpha, 3x beta
Rotation of c ring driven by
c ring
Where is the proton binding site on c subunits
Carboxylate side chain of asparatate or glutamate
alpha/beta bind to adenine, but only ___ has catalytic activity
beta
ADP*Pi binds
Loose
ATP in
Tight
Release ATP in
Open
Regulation of oxidative phosphorylation (ETC)
1) Availability of reduced cofactors drives oxidative phosphorylation (need NADH/QH2)
2) Needs ADP and Pi to make ATP
3) Mitochondria has regulatory protein that binds to ATP synthase and inhibits hydrolysis: pH sensitive. Binds if matrix PH drops due to momentary disruption of gradient. Prevents it from going in reverse.
l
Why does proton gradient not build up beyond typical 0.75 pH unit difference?
As soon as protons pumped into intermembrane spade, return to matrix via c ring of ATP synthase.
