How can we help?

You can also find more resources in our Help Center.

29 terms

Biochem - Lipid Metabolism 1 (beta oxidation)(slides 13-23)

STUDY
PLAY
the first step in beta oxidation is the conversion of the free fatty acid to its __ __
CoA ester
once the fatty acid is converted to its CoA ester, the second step in beta oxidation is the transport into the ___ ___
mitochondrial matrix
once the CoA ester is transported into the mitochondrial matrix, it undergoes a sequence of 4 repetitive steps:
1) dehydrogenation
2) hydration
3) dehydrogenation (a second one)
4) carbon-carbon cleavage (thiolase reaction)
each cycle of the 4 steps in the mitochondrial matrix lops off __ carbon atoms
2
where does the esterification of the free fatty acid with CoA occur?
outer mitochodondrial membrane
what enzyme catalyzes the reaction of a fatty acid to its CoA ester?
Acyl CoA synthetase
acyl CoA synthetase couples with the cleavage of __ to __and ___ in the reaction of fatty acid -> CoA ester
ATP, AMP, pyrophosphate (PPi)
what drives the entire reaction of fatty acid -> CoA ester strongly to the right?
breakdown of pyrophosphate (to inorganic phosphate)
in general, __ is an enzyme that utilizes ATP, whereas __ does not use ATP
synthetase, synthase
how many high energy phosphate bonds (ATP) are lost in the reaction of fatty acid -> CoA ester?
2
is the CoA fatty acid ester able to pass through the inner mitochondrial membrane?
no
fatty acids esterified with __ are capable of being transported across the inner mitochondrial membrane
carnitine
the enzyme __ __ converts the fatty acid CoA ester to the O-acylated carnitine which is transported across the mitochondrial membrane by the transporter
carnitine acyltransferase I (CA1)
once on the matrix side of the inner mitochondrial membrane, the acylated carnitine is transformed by carnitine acyltransferase II (CA2) back into the __ __ ___
fatty acyl CoA
O-acylcarnitine is transported across the inner mitochondrial membrane by __/__ shuttle
acylcarnitine/carnitine
enzyme __ occurs only in outer membrane of mitochondria
CA1
__ reforms the CoA ester and releases carnitine
CA2
once inside the mitochondrial matrix, the fatty acyl CoA ester undergoes 4 reactions, the first reaction is catalyzed by __ __ __ and __ is converted to __ in the process
acyl CoA dehydrogenase, FAD, FADH2
the double bond that is formed in the first dehydrogenation reaction of fatty acyl CoA ester in the mitochondrial matrix has a __ stereochemistry
trans
in the second reaction of fatty acyl CoA in the mitochondrial matrix, __ is added across the double bond and the enzyme used is __ __ __
water, enoyl CoA hydratase
the third reaction in the sequence of 4 reactions that occurs in the mitochondrial matrix is another __ reaction, but in this case, the alcohol is oxidized to a ketone using __ as the oxidizing agent
dehydrogenation, NAD+
the b-ketoacyl CoA formed in the third step in the mitochondrial matrix is catalayzed by __ which cleaves off a molecule of acetyl CoA, leaving the __ __ of the original fatty acid but with __ less carbon atoms
thiolase, CoA ester, 2
__ and __ are generated in beta oxidation
FADH2, NADH
the 4 reaction sequence is repeated, losing 2 carbon atoms each cycle, in the final reaction sequence in which the 4-carbon butyroyl CoA thioester is oxidized, the final thiolase reaction produces two molecules of __ __
acetyl CoA
example of beta oxidation: palmitoyl CoA (16 carbon atoms) goes through _ cycles of beta oxidation and is completely broken down to __ molecules of acetyl CoA, generating _ FADH2 and _ NADH
7, 8, 7, 7
how many molecules of ATP are generated from FADH2 when palmitoyl CoA (16 carbons) undergoes the beta oxidation process?
10.5 (takes 7 cycles, forms 7 FADH2, 1 FADH2 = 1.5 ATP, 7X1.5 = 10.5)
how many molecules of ATP are generated from NADH when palmitoyl CoA (16 carbons) undergoes the beta oxidation process?
17.5 (takes 7 cycles, forms 7 NADH, 1 NADH = 2.5 ATP, 7x2.5 = 17.5)
how many molecules of ATP are formed for every molecule of palmitoyl CoA that is completely oxidized (beta oxidation plus citric acid cycle) to carbon dioxide and water?
106 (not 108, have to subtract 2 ATP b/c we have to use them in esterification to get the faty acid into the system)
under intracellular conditions, free energy recovery is remarkably ___
efficient