Enzymes/regulation

Question 0

Glyceraldehyde-3-Phosphate Dehydrogenase

Answer 0

G3P + NAD+ + Pi 1,3-BPG + NADH

Inhibited by Arsenate

Question 1

PFK-1

Answer 1

F6P -> F-1,6-bP

Activators: AMP, F-2,6-bP
Inhibitors: physiologic [ATP], Citrate(during fatty acid de novo synthesis), low pH (important in RBCs)

Question 2

Enolase

Answer 2

2-PG PEP

Inhibited by fluoride

Question 3

Irreversible steps glycolysis

Answer 3

Hero/gluco kinase
PFK1
PK

Question 4

Substrate level phosphorylation glycolysis

Answer 4

PK

G3PD

Question 5

Pyruvate dehydrogenase complex

Answer 5

3 enzymes
Uses TPP, lipoid acid, CoA, FAD, NAD

ACTIVATORS: Ca2+, Mg2+ (activate phosphotase), pyruvate (inhibit kinase), de phosphorylation, insulin, catechilamines

INHIBITORS: ATP(activate kinase), NADH&Ac-CoA (product inhibition and activate kinase), phosphorylation

Question 6

Citrate synthetase

Answer 6

Activators: Ca2+, ADP

Inhibitors: ATP, NADH, succinyl-CoA, fatty acyl CoA

Question 7

Isocitrate dehydrogenase

Answer 7

Activated: ADP, Ca2+

Inhibited: ATP NADH

Question 8

aKgDH

Answer 8

Act: Ca2+

Inhibit: ATP GTP NADH Succinyl-CoA

Question 9

Succinate dehydrogenase

Answer 9

Act: ADP Pi succinate
Inh: OAA

Question 20

Complex 1

Answer 20

NADH dehydrogenase
FMNFMNH2
CoQH2CoQ

Rotenone, pericidin A, Amytal

Question 21

Complex 2

Answer 21

Succinate dehydrogenase
FADFADH2
CoQH2CoQ
Doesn’t pump protons

Question 22

Complex 3

Answer 22

Cytochrome reductase
Cyto bc1
Gives to cyto c

Antimycin A

Question 23

Complex 4

Answer 23

Cytochrome oxidase
From cyt c
Uses cyt a+a3

H2S, azide, CO, cyanide

Question 24

Ac-CoA

Answer 24

Up-pyruvate carboxylase

Down-PDH, G6PD

Question 25

Pyruvate carboxylase

Answer 25

Needs Ac-CoA (absolute allosteric activator, not part of catalysis) and biotin

Question 26

Pep carboxykinase

Answer 26

Used GTP OAA to GTP

Question 27

PKA acts on:

Answer 27

Acts on: glycogen synthase (off), phosphorylase kinase (on), pyruvate kinase(liver only, off), bifunctional (f-2,6-bpase on, pfk2 off)

Question 28

NADH

Answer 28

Off: PDH(kinase on and product), aKgDH, IDH, favors reversal of MDH(make malate)

Question 29

Fructose-1,6-bisphosphotase

Answer 29

Inhibited by: AMP, F-2,6-bP

Question 30

F-2,6-bP

Answer 30

Up pfk1

Down f-1,6-bpase

Question 31

AMP regulates:

Answer 31

Pfk1-up
F-1,6-bpase-down
Myophosphorylase->up
AMP kinase->synthesis of GLUT4. (Muscles)

Question 32

Hexokinase regulation

Answer 32

Inhibited by high [g6p] (product inhibition). Does not affect gluco kinase (high km)

Question 33

Glucokinase regulation

Answer 33

Sequestered in nucleus by gluco kinase regulatory protein (GKRP) at high [F-6-P]. Moved to cytosol at high [glucose]. Beta cells. Also signals insulin production

Question 34

Pyruvate kinase regulated by

Answer 34

PKA-liver, off
F-1,6-bP -> on: liver, RBCs, proliferating cells (has higher affinity in other tissues)
Alanine->liver, off (alanine-glucose cycle)
ATP->off

Question 35

ATP regulates:

Answer 35

PFK1-off
PK-off
PDH-off
Citrate synthase-off
IDH-off
AKgDH-off
Glycogen phosphorylase-off

Question 36

Induced by Insulin

Answer 36

Glucokinase, bifunctional enzyme, pfk1, PK

Question 37

Glucagon induces

Answer 37

Pep carboxykinase, f-1,6-bpase, g6pase

Question 38

Cortisol induces

Answer 38

Pep carboxykinase

Question 39

Glucagon represses

Answer 39

Pfk1, glucokinase, PK

Question 40

NADH regulates

Answer 40

PDH-off
Citrate synthase-off
IDH-off
AKgDH-off
LDH to pyruvate
MDH to malate
Glyceraldehyde 3PDh to G3P (probably)

Question 41

Ca2+

Answer 41

Released by IP3 in alpha1adrenergic receptor and in muscles on contraction

Activate: PDH, citrate synthase, IDH, aKgDH, myophosphorylase kinase

Question 42

ADP regulates:

Answer 42

Up: IDH, Succinate dehydrogenase, citrate synthetase

Question 43

Glycogen synthase

Answer 43

Act: protein phosphotase 1 (insulin)
Inact: PKA (glucagon)

Allosterically activated by glucose 6 phosphate

Question 44

Glycogen phosphorylase

Answer 44

Inhibited: g6P, ATP, glucose (liver)
Activated: AMP (muscle)