10/22 Pyruvate Flashcards
where does pyruvate come from, and what does it become
end product of glycolysis
if O2, enters TCA cycle and becomes AcCoA
if no O2, converted to lactate to genenerate NAD+ (4 mol ATP per glucose)
what happens to pyruvate after it’s anaerobically converted to lactate
include enzyme that transports it out of the cell
exported from cells by monocarboxylate transporter
to liver to keep blood lactate low to prevent ketoacidosis
Cori Cycle
recycles lactate from mm to liver, then from liver back to mm as glucose, requires energy
2 lactate : 1 glucose
glucose-alanine cycle
in mm, glu–>pyruvate —>(plus -NH2 from AA)—> alanine –> blood
liver: alanine splits into
1) -NH2 (for urea cycle)
2) pyruvate –> glu –> peripheral tissues
remember alanine is major carrier of nitrgen in the blood
pyruvate dehydrogenase complex (PDC/PDH)
primary link between glycolysis and TCA
pyruvate —–(irreversible)—–> Acetyl CoA
3 subunits (E1, E2, E3)
requirement/fxn of E1 of PDC
TPP
decarboxylation
same as yeast ethanolic fermentation
requirement/fxn of E2 of PDC
Lipoate and CoA
generation of acetyl CoA
requirement/fxn of E3 of PDC
FAD and NAD+
regeneration of NADH
sources of pyruvate for FA synthesis
1/2 from malic enzyme
1/2 from PPP
rate limiting step of gluconeogenesis
phosphoenolpyruvate carboxykinase
OAA –> phosphoenol pyruvate –> pyruvate
consequences of statins
inhibits mevalonate pathway
lower cytosolic:
farnesyl PP
geranyl PP
ubiquinone
must supplement with CoQ10
sialic acid
cell surface recognition molecule, contains pyruvate from phosphoenol pyruvate
pyruvate is a breakdown of which amino acids?
G-CATS
glycine cysteine alanine threonine serine
warburg effect
in cancer cells, even though there is O2, they prefer anaerobic glycolysis (85% of pyruvate –> lactate), avoiding mitochondria might help avert apoptosis
change from PKM1 to PKM2
what drug attempts to circumvent warburg effect
dichloroacetate
inhibits pyruvate dehydrogenase kinase, reactivates PDH and oxidative phosphorylation
