Bio chem test 2: Control of Citric Acid cycle/ pyruvate dehydrogenase complex

what are the two fates of acetyl CoA

enter the citric acid cycle and incorporation into lipids

how is the activity of pyruvate dehydrogenase complex controlled

allosterically and by reversible phosphorylation

what products of the pyruvate dehydrogenase complex allosterically inhibit it

immediate products, acetyl CoA and NADH and ultimate product, ATP

high concentrations of acetyl Coa inhibits

the transacetylase (E2) component of pyruvate dehydrogenase complex

NADH inhibits what proportion of pyruvate dehydrogenase complex

E3 (dihydrolipoyl dehydrogenase)

pyruvate dehydrogenase kinase (PKD)

phosphorlyates pyruvate dehydrogenase component (E1)

what is the effect of pyruvate dehydrogenase kinase (PKD) on the pyruvate dehydrogenase complex

inactivates the complex

pyruvate dehydrogenase phosphatase

dephosphorylates E1 making it active again

does phosphorylating pyruvate dehydrogenase activate or inactivate it

inactivate

PDK uses

ATP

what activates the pyruvate dehydrogenase complex

pyruvate and ADP

what inhibits pryuvate dehydrogenase kinase

pyruvate and ADP

in high energy charge, the pyruvate dehydrogenase complex is

inhibited, don't need the energy have enough ATP

in low energy charge, the pyruvate dehydrogenase complex is

activated, have ADP

at rest ratios of NADH/NAD+, acetyl CoA/CoA and ATP/ADP are

high which promotes phosphorylation and inactivation

during activity ADP and pyruvate inhibit pyruvate dehydrogenase kinase and

CA stimulates the phosphatase enhancing activation

if you have deficiency in pyruvate dehydrogenase phosphatase what is glucose processed to

lactate resulting in lactic acidosis

diabetic neuropathy may be due to

inhibition of the pyruvate dehydrogenase complex and overproduction of lactic acid

hyperglycemia _____ pyruvate dehydrogenase kinase activity

increases leading to more pyruvate dehydrogenase complex inhibition

the citric acid cycle is primarily regulated by

concentrations of ATP and NADH

what are the allosteric enzymes of the citric acid cycle

isocitrate dehydrogenase and a-ketoglutarate dehydrogenase (thermodynamically irrverisible steps)

anapldrotic reactions

intermediates in a pathway are regenerated

example of anapldrotic reaction in the citric acid cycle

oxaloacetate from pyruvate by pyruvate carboxylase

BeriBeri

a neurologic and cardiovascular disorder

what is BeriBeri caused by

deficiency in thiamine

what is thiamine the precursor of

cofactor TPP

patients with beriberi have

higher than normal levels of pyruvate and a-ketoglutarate

mercury and arsenite inhibit

pyruvate dehydrogenase complex

what do mercury and arsenite bind to to inhibit the pyruvate dehydrogenase complex

dihydrolipoyl groups of the E3 component of pyruvate dehydrogenase complex

two drugs for the treatment of Hg and AsO3 poisoning

dimercaprol and succimer

remove Hg or AsO3 off the enzyme