LECTURE 24 Flashcards
CHECK ON LEARNING
common in many lipids and in TG?
palmitic acid
stearic acid
oleic acid
how many carbons comprise palmitic acid?
16:0
how many carbons comprise stearic acid?
18:0
how many carbons comprise oleic acid?
18:1
these are essential FA’s because we can’t synthesize them?
linoleic acid
linolenic acid
how many carbons comprise linoleic acid?
18:2
how many carbons comprise linolenic acid?
18:3
this is a fatty acid made from linoleates and is precursor of PGs?
arachidonic acid
how many carbons comprise arachidonic acid?
20:4
these contain FAs of 24 carbons, so name this FA and example?
cerebrosides
nervonic acid
where does fatty acid synthesis primarily occur?
Liver and mammary cells
where does fatty acid synthesis start? describe the initial step that starts the process?
mitochondrial matrix of the liver and mammary cells
AcCoA to citrate via citrate synthase with OAA in the mitochondrial matrix then into the cytosol via citrate transporter and converted to Acetyl CoA via citrate lyase where OAA is also released
what converts the AcCoA to malonyl CoA? why is this significant?
stimulated by?
inhibited by?
keep in mind that malonyl CoA is converted to malonyl ACP, what enzyme is this?
acetyl CoA carboxylase
key regulatory enzyme for fatty acid synthesis
stimulated by citrate and insulin
inhibited by malonyl CoA, palmitoyl CoA and epinephrine
malonyl transacylase
what energizes AcCoA? what is the necessary cofactor for holding the activated CO2?
carboxylation
biotin
what converts Acetyl CoA to Acetyl ACP?
acetyl transacylase
how does the cycle continue when we finally have the ACP substrates, just name the important concepts?
both converted to acetoacetyl-ACP via acyl-malonyl ACP condensing enzyme
this is converted to D-3 hydroxybutyric ACP by B-ketoacyl-ACP reductase, NADPH is also used
D-3 hydroxybutyric ACP to Crotonyl-ACP via 3-hydroxyacyl-ACP dehydratase, H2O released
Crotonyl-ACP to Butyric ACP via enoyl ACP reductase, another NADPH used
what can Acetyl CoA use in place of AcCoA? what is unique about the carbon yield
Propional CoA which yields FAs with odd# of carbons
what are the products after fatty acid synthesis is finished?
8 AcCoA with 7 ATPs, 14 NADPHs used and 7 HCO3 to yield palmitate, 8 CoA, 7 ADP, 14 NADP, 7 CO2, 7 Pi
what is the other source for NADPH?
citrate to acetyl CoA than to the fatty acid synthesis cycle
how is palmitate made into longer chains and can become unsaturated if this is the product?
it goes to the mitochondria or microsome on the ER where malonyl CoA is added to the carboxyl end of the acyls to elongate them
what is a TAG comprised of?
glycerol and 3 fatty acids
where does most denovo synthesis of TGs occur?
liver and adipocytes
what converts the DHAP and glycerol -PO4?
glycerol-PO4 dehydrogenase providing the backbone to build off
what are the sources for glycerol-PO4 synthesis?
liver and cytosol
what activates the fatty acid, the glycerol-PO4 to start the elongation process?
in this process what is the simplest phospholipid? the second messenger?
this final product is stored in the liver or packaged in VLDLs for export to the body?
fatty acyl CoA synthase
phosphatidate
diacylglycerol
TAG
