Topic 7: Fatty acid metabolism Flashcards
what type of metabolism is fatty acid metabolism
stage 2
in mitochondria
how does fatty acid catabolism work
- fatty acid activated by linking to coA
- transporter across inner mitochondrial memrbane using a carnitine shuttle
- cycles through sequences of oxidative reactions in which 2 carbons are removed in each cycle
C18-> C16 + C2
so both NAD+ and FAD+ reduced
how are fatty acids activated
in cytoplasm
by linking to coA by a higher energy bond by action of fatty acyl coA synthase (uses hydrolysis of ATP to drive it)
require specific mechanism to allow transport of activated fatty acids across inner membrane (CARNITINE SHUTTLE)
how does the carnitine shuttle work
fatty acyl coA + carnitine catalysed by CAT1 = acyl carnitine, with release of coA
acyl carnitine taken up by shuttle transporter into matrix
reacted upon by CAT2 to convert back to acyl coA + carnitine
carnitine is exchanged across membrane
how is carnitine shuttle regulated
inbibited by malonyl-coA
what defects can occur in the carnitine shuttle
exercise intolerance - unable to use high energy compounds
lipid droplets in muscle
what is fatty acid catabolism also known as
beta oxidation
how is fatty acid characterised
multiple steps oxidative loss of 2 carbons each time lots of acetyl coA (enter krebs cycle) forms a 2 C acetyl coA product and a shorter acyl coA to re-enter cycle NADH nad Fadh2
which oxidation produces more energy, glucose of fatty acid
fatty acid (41ATP in comparison 32moles for C6, but all of fatty acid - 123ATP) due to being more reduced so higher energy content
how is glycerol metabolised
to liver
glycerol kinase + some ATP -> glycerol phosphate
this can form triacylglycerol or acted upon y NAD+ to oxidise to DHAP into glycolysis
can fatty acid metabolism occur without O2
no
which enzyme facilitates the activation of fatty acids by linking CoA
fatty acyl coA synthase
