Transcript 12ppt - UCSD Course Websites

Lecture 12 Slides
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Anabolism!!!
part II intro fig4
Gluconeogenesis
anabolic production of glucose
Carbohydrates
a two-lane
highway…
fig 14-16
what determines
these special
steps?
The glycolysis energy landscape
(pyruvate set to 0)
First bypass
fig 14-17
First bypass, second step PEPCK
fig 14-17
The glycolysis energy landscape
(pyruvate set to 0)
Three big steps down… or up
table 14-2
First bypass
fig 14-17
WHICH
TISSUES
can do
GLUCONEOGENESIS?
WHICH TISSUES can do GLUCONEOGENESIS?
1) LIVER
2) KIDNEY
fig 15-20
WHICH TISSUES can do GLUCONEOGENESIS?
1) LIVER
2) KIDNEY
fig 15-20
Three big
steps on the
way up…
fig 14-16 top
HOW DOES THE LIVER
DECIDE WHETHER TO DO
GLUCONEOGENESIS
or GLYCOLYSIS?
fig 15-20
Two fates for pyruvate
regulation by
AcCoA
abundance
fig 15-20
Fructose bisphosphate is at a key position in both cat and ana
Remember regulation of PFK-1??
fig 15-15
pg 581
When glucose is abundant, so is F2,6BP
F2,6BP accelerates
PFK-1
fig15-16
When glucose is low, so is F2,6BP
F2,6BP inhibits
FBPase
fig 15-16
When glucose is low, so is F2,6BP
When glucose is abundant, so is F2,6BP
fig 15-16
Separate distinct enzyme activities control Fr2,6BP levels
fig 15-17
…and hormones control these enzymes
fig 15-17
WHAT ARE THE
CARBON SOURCE(S)
FOR
GLUCONEOGENESIS?
fig 15-20
CARBON SOURCE(S) FOR GLUCONEOGENESIS?
1) Lactate
fig 15-20
CARBON SOURCE(S) FOR GLUCONEOGENESIS?
2) Glycerol
fig 15-20
lipid menagerie (BLAST from the PAST)
phospholipid
triglyceride
CARBON SOURCE(S) FOR GLUCONEOGENESIS?
3) Amino acids
fig 15-20
table 14-4
CAN WE USE
FATTY ACIDS
for
GLUCONEOGENESIS?
Can you make glucose from fat using Krebs?
Fat breakdown produces AcCoA (later…)
Krebs cycle converts AcCoA to OAA
OAA can be converted to PEP (PEP-CK)
PEP is the rate-limiting step for synthesis of
glucose (later…)
so, why not?
every time you put an acetate in
two CO2 come out before you get to OAA!
KREBS! (BLAST from the PAST)
fig 16-13
CAN ANY ORGANISM
USE
FATTY ACIDS
for
GLUCONEOGENESIS?
The Glyoxylate
Cycle
fig 16-20
fancy
Glyoxylate
Cycle:
an
end run
around
carbon
loss
isocitrate
lyase
malate synthase
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Plants: the Kings of Glyoxylate…
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Glyoxylate cycle:
a cellular
biochemist’s
view…
fig 16-22 (sort of)
Glyoxylate cycle:
a cellular
biochemist’s
view…
fig 16-22
Glyoxylate cycle:
a cellular
biochemist’s
view…
fig 16-22
Glyoxylate cycle:
a cellular
biochemist’s
view…
fig 16-22
The Biochemical Bottom Line:
Krebs
Acetyl-CoA + 3 NAD+ + FAD + GDP + Pi + 2 H2O
→
CoA-SH + 3 NADH + 3 H+ + FADH2 + GTP + 2 CO2
Glyoxylate
2 Acetyl-CoA + NAD+ → succinate + NADH + H+
fig 16-22
Speaking of plants..
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RUBISCO: ribulose
Plants make glucose from… CO2 by
photosynthesis
Optical processes (light-dependent
reactions) generate ATP and NADPH
by use of electron transport and H+
gradients
Biochemical reaction “fixes” CO2 to
make 3 carbon precursor…
RUBISCO: ribulose-bis-phosphate carbolxylase
Plants use gluconeogenesis to make glucose
from the 3PG made by rubisco…
DHAP
3PG
Fr1,6bP
1,3bPG
G3P
ATP and NADPH are employed
as the expected substrates
in this process
etc