Enzymes/regulation Flashcards
Glyceraldehyde-3-Phosphate Dehydrogenase
G3P + NAD+ + Pi 1,3-BPG + NADH
Inhibited by Arsenate
PFK-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)
Enolase
2-PG PEP
Inhibited by fluoride
Irreversible steps glycolysis
Hero/gluco kinase
PFK1
PK
Substrate level phosphorylation glycolysis
PK
G3PD
Pyruvate dehydrogenase complex
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
Citrate synthetase
Activators: Ca2+, ADP
Inhibitors: ATP, NADH, succinyl-CoA, fatty acyl CoA
Isocitrate dehydrogenase
Activated: ADP, Ca2+
Inhibited: ATP NADH
aKgDH
Act: Ca2+
Inhibit: ATP GTP NADH Succinyl-CoA
Succinate dehydrogenase
Act: ADP Pi succinate
Inh: OAA
Complex 1
NADH dehydrogenase
FMNFMNH2
CoQH2CoQ
Rotenone, pericidin A, Amytal
Complex 2
Succinate dehydrogenase
FADFADH2
CoQH2CoQ
Doesn’t pump protons
Complex 3
Cytochrome reductase
Cyto bc1
Gives to cyto c
Antimycin A
Complex 4
Cytochrome oxidase
From cyt c
Uses cyt a+a3
H2S, azide, CO, cyanide
Ac-CoA
Up-pyruvate carboxylase
Down-PDH, G6PD
Pyruvate carboxylase
Needs Ac-CoA (absolute allosteric activator, not part of catalysis) and biotin
Pep carboxykinase
Used GTP OAA to GTP
PKA acts on:
Acts on: glycogen synthase (off), phosphorylase kinase (on), pyruvate kinase(liver only, off), bifunctional (f-2,6-bpase on, pfk2 off)
NADH
Off: PDH(kinase on and product), aKgDH, IDH, favors reversal of MDH(make malate)
Fructose-1,6-bisphosphotase
Inhibited by: AMP, F-2,6-bP
F-2,6-bP
Up pfk1
Down f-1,6-bpase
AMP regulates:
Pfk1-up
F-1,6-bpase-down
Myophosphorylase->up
AMP kinase->synthesis of GLUT4. (Muscles)
Hexokinase regulation
Inhibited by high [g6p] (product inhibition). Does not affect gluco kinase (high km)
Glucokinase regulation
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
Pyruvate kinase regulated by
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
ATP regulates:
PFK1-off PK-off PDH-off Citrate synthase-off IDH-off AKgDH-off Glycogen phosphorylase-off
Induced by Insulin
Glucokinase, bifunctional enzyme, pfk1, PK
Glucagon induces
Pep carboxykinase, f-1,6-bpase, g6pase
Cortisol induces
Pep carboxykinase
Glucagon represses
Pfk1, glucokinase, PK
NADH regulates
PDH-off Citrate synthase-off IDH-off AKgDH-off LDH to pyruvate MDH to malate Glyceraldehyde 3PDh to G3P (probably)
Ca2+
Released by IP3 in alpha1adrenergic receptor and in muscles on contraction
Activate: PDH, citrate synthase, IDH, aKgDH, myophosphorylase kinase
ADP regulates:
Up: IDH, Succinate dehydrogenase, citrate synthetase
Glycogen synthase
Act: protein phosphotase 1 (insulin)
Inact: PKA (glucagon)
Allosterically activated by glucose 6 phosphate
Glycogen phosphorylase
Inhibited: g6P, ATP, glucose (liver)
Activated: AMP (muscle)
