Citronsyrecyklussen Flashcards
components of pyruvat dehydrogenase complex
pyruvate dehydrogenase E1
dihydrolipoyl transacetylase E2
dihydrolipoyl dehydrogenae E3
Aminoacids can enter this cycle as
acetate, malate or succinate
Warburg effect in terms of pyruvate oxidation
slows down the oxidation
How many cofactors does PDH-complex have
what is it subject to
5 cofactors 4 are derived from vitamines
subject to covalent modification and steric regulation
Enzymes and coenzymes in PDH-complex
3 enzymes: dihydrolipoyl dehydrogenase + dihydrolipoyl transacetylase + pyruvate dehydrogenase
5 coenzymes fra hvilke vitaminer
TPP (thiamine) NAD (niacin) FAD (riboflavin) CoA (pantothenate) Lipoate
where do TPP, FAD and lipoate bind to?
E1, E3 and E2
what produces the flexible arm between E1 and E3
lipoate when binding to lysin at the end of E2
what is meant by substrate channeling
the intermediates never leave the enzyme
how many oxidation reactions are there in the citric acid cycle
4
what does aconitase have in the active site that helps bind the substrate
iron-sulfur center
Aconitase and iron homeostasis
regulates it when iron is depleted
moonlighting enzymes
enzymes having more than one job
types of isocitrate dehydrogenase
1- in mitochondria (using NAD+)
2- In the cytosol using NADP+ for anabolic processes
when is CO2 produced in Citric acid cycle
from isocitrate -> alpha ketoglutarate
from alpha ketoglutarat -> succinyl-CoA
what metal does isocitrate dehydrogenase have at the active site
Mg2+
phosphorylases?
Phosphate groups attacking the cleavage points
ligase
condensation reactions using energy
what can malonyl-CoA inhibit
carnitin acyltransferase I and succinate dehydrogenase
the conversion of malate –> oxaloacetat
is very endergonic but coupled with very exergonic citrate formation
what is an amphibolic pathway
pathway that is anabolic and catabolic
what does avidin do
binds to biotin and prevents its absorption in the intestines
anaplerotic reactions in glycolysis
formation of oxaloacetate or malate from pyruvate or PEP
By what and how is PDH activated?
by phosphoprotein phosphatase, by removing a phosphoryl group
where is the citric acid cyle regulated?
citrate synthase
pyruvate dehydrogenase
a-ketoglutarat dehydrogenase + aconitase
transport of pyruvate into mitochindria using (MPC) mitochondrial pyruvate Carrier
