Lecture 12 Slides rh

Anabolism!!! part II intro fig4

Gluconeogenesis anabolic production of glucose

Carbohydrates a two-lane highway… what determines these special steps? fig 14-16

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?

Fat breakdown produces AcCoA (later…) 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 fancy fig 16-20

Glyoxylate Cycle: an end run around carbon loss isocitrate lyase malate synthase rh

Plants: the Kings of Glyoxylate… rh

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.. rh

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 Fr1,6bP 3PG 1,3bPG etc G3P ATP and NADPH are employed as the expected substrates in this process