ch 18

what is the fuel for the CAC and converted to what

acetyl CoA which is converted to CO2

what are the two fates of acetyl CoA

CAC in mito or fatty acid synthesis in cytosol

what does PDC do for CAC

prepares pyruvate from glycolysis

where does PDC happen and how is pyruvate transported for this

mitocondrial matrix, by carriers MPC1 and MPC2

what is the overall reaction of PDC

pyruvate, CoA, NAD+ > acetyl CoA, NADH, H+, CO2

how many reactions are there in PDC and how many enzymes needed

three: decarboxylation, oxidation, transfer to CoA, five

what are the stoichiometric coenzymes of PDC

NAD+, CoA function as substrates

what are the catalytic coenzymes of PDC

TPP, lipoamide, FAD, reset after each cycle

what happens in decarboxylation

catalyzed by pyruvate dehydrogenase, pyruvate + TPP > hydroxyethyl-TPP +CO2

what happens in oxidation

catalyze by E1 again and lipoamide arm, two carbon fragment is oxidized and transferred to lipoamide having a thioester bond, TPP carbanion restored

how is the lipamide arm formed

attaching lipioc acid to lysine from E2

what happens during the transfer to CoA step

catalyzed by E2, thioester bond made between the two, regeneration of lipamide by E3, FAD>FADH2>NADH

where is the first full oxidation of a carbon from glucose

PDC where glucose can’t be remade

what products inhibit PDC

Acetyl CoA-E2 NADH-E3

how is PDC regulated with phosphates

E1 either has it added by PDH kinase to make inactive or removed by PDH phosphatase to make active

when PDH kinase inactivates PDC what is high

NADH, ATP, Acetyl CoA

what inhibits PDH kinase

ADP, pyruvate

what is PDH phosphatase activated by

epinephrine/calcium and insulin

how does defective PDH phosphatase cause lactic acidosis

PDC stuck inactive, pyruvate fermented making lactate and acid

what happens when there is a thiamine (in TTP) deficiency

reduced PDC activity

how can mercury affect PDC/ what does it bind to

binds to E2