Lipid Metabolism Flashcards
major sites of fatty acid synthesis
liver, lactating titties
minor sites of fatty acid synthesis
kidney, adipose tissue
precursors of FA synthesis
Acetyl CoA, ATP, NADPH, CO2, Biotin
FA synthesis occurs where
cytoplasm, son.
configuration of double bonds in unsaturated FA
cis
location of double bonds in linolenic acid
9, 12, 15
location of double bonds in arachidonic acid
5, 8, 11, 14
key intermediate between fat and carbohydrate metabolism
acetyl CoA
main source of acetyl CoA for FA synthesis
pyruvate
how does acetyl CoA get into the cytoplasm
converted to Citrate via citrate synthase
after citrate is in the cytoplasm, what breaks it down to acetyl CoA and OAA
ATP-Citrate lyase
enzyme that produces NADPH in cytoplasm for FA synthesis
malic enzyme
rate limiting enzyme for FA synthesis
Acetyl CoA Carboxylase (ACC)
ACC coenzyme needed
biotin. (because of carboxylase)
first committed step of FA synthesis
acetyl CoA to malonyl CoA via ACC
shifts ACC toward inactive dimer form
palmitoyl CoA (allosteric regulation)
shifts ACC toward active polymer form
Citrate (allosteric regulation)
short term inactive regulation of ACC is done by which hormones
glucagon, epi and NE.
explain how ACC is phosphorylated due to glucagon presence
cAMP activates pKA. pKA phosphorylates AMPKK, AMPKK phosphorylates AMPK which phosphorylates ACC to make it inactive.
FAS can exist as a monomer or dimer. which form is more active
dimer
where do the carbons come from when elongating fatty acetyl chain
malonyl CoA. (gives off 2 carbons per molecule)
what does FAS need to work
NADPH
fatty acyl desaturation & elongation takes place where
ER
enzyme that introduces sites of desaturation.
fatty acyl CoA desaturase
