Fatty Acid, Triacylglycerol, and Ketone Metabolism Flashcards
what is hormone-sensitive lipase’s substrate? What product does it produce
subtrate: diacylglycerols
produces: monoacylglycerol
phosphorylation of which protein is needed in order for lipases to gain access to the lipid droplet
-perilipin
does pyrophosphatase play a role in fatty acid oxidation?
yes, it cleaves the PPi from the ATP with adenylyl cyclase which according to LeChatlier’s principle helps produce more cAMP
where does Beta oxidation occur? Describe how the long chain fatty acid gets there
B-oxidation occurs in the mitochondrial matrix
-long chain fatty acids rely on a transport system to get there
-long chain fatty acids can cross the outer mitochondrial membrane relatively easily due to the large pores present
-fatty acids must react with ATP and CoA to form fatty acyl CoA.
on the outer mitochondrial membrane is an enzyme, carnitine -palmitoyl transferase 1 which catalyzes the reaction of fatty acyl CoA with carnitine to form acyl-carntine
-acyl-carnitine can get transported across the anti-porter called translocase which puts acyl-carnitine into the mitochondrial matrix while pushing carnitine out
-on the inner mitochondrial membrane is carnitine-palmitoyl transferase II which regenerates the fatty acyl CoA
how many B oxidation enzymes are there
- dehydrogenase
- hydratase
- dehydrogenase
- thiolase
describe how to do the calculations for B-oxidation: even number, saturated fatty acids
number of acetyl CoA’s = number of carbons/2
number of times oxidized = number of acetyl CoAs - 1
how many ATPs are produced by each acetyl CoA at the TCA cycle?
~12 ATP
the regulation of fatty acid oxidation is really a matter of ____ getting ____ and _____ being ____ in adipose tissue
perilipin phosphorylated
hormone sensitive lipase phosphorylated
but not a super dramatic increase in FFA in blood**
T/F: hormone sensitive lipase is sensitive to increases in glucagon concentrations
False: no glucagon receptors. Epinephrine is the “activator” here
Considering Fatty acid oxidation and regulation: Insulin has an ___ effect and will stimulate ___ which will _____ hormone sensitive lipase rendering it ____
-inhibitory
-phosphatase
dephosphorylate
-inactive
for oxidizing fatty acids with double bonds, what are the energy consequences?
-one less FADH2 for each double bond because we can pick up the pathway at the hydratase of the enol
what are three possible fates for glucose 6-P
- glycolysis
- glycogen synthesis
- hexose monophosphate shunt
what are the two local regulatory molecules for acetyl CoA carboxylase?
- citrate (+)
- long chain fatty acyl CoAs (-)
what are the hormonal regulatory molecules on acetyl CoA carboxylase?
insulin (+)
glucagon(-)
epinephrine (-)
which form of acetyl CoA carboxylase is active: phosphorylated or not?
NOT. Consider how insulin stimulates protein phosphatase which removes phosphate groups. Since insulin + acetyl CoA caboxylase, it makes sense that the dephosphorylated kind is the active
