Glycolysis, Gluconeogenesis, and the

1
Chapter 14
Glycolysis, Gluconeogenesis, and the Pentose
Phosphate Pathway Part 1 Glycolysis
2
Glycolysis
Key topics Things to Know

• Chemistry of each glycolytic reaction Forwards
  and Backwards.
• The general thermodynamics of each reaction.
• Other sugars entry to glycolysis.
• What to do with Pyruvate?

3
Central Importance of Glucose

• Glucose is an excellent fuel
• Yields good amount of energy upon oxidation
• Can be efficiently stored in the polymeric form
• Many organisms and tissues can meet their energy
  needs on glucose only
• Glucose is a versatile biochemical precursor
• Bacteria can use glucose to build the carbon
  skeletons of
• All the amino acids
• Membrane lipids
• Nucleotides in DNA and RNA
• Cofactors needed for the metabolism

4
(No Transcript)
5
Discoverers of Glycolysis (EMP Pathway)
Jacob Parnas 1884-1948
6
Showed that the sugar intermediates were
Phosphorylated
7
Glycolysis Overall
1 Glucose ? 2 Pyruvates 2ATP 2 NADH 10
Reactions Know them Backwards and
Forwards!!!! Where is this going on in a cell?
EOC Problems 12 can be worked from this Figure
and Lactate Dehydrogenase Rxn (slide 35)
8
Another View of Glycolysis What is This?? from
KEGG Pathways Linked to Glycolysis, Enzymes by
EC numbers
9
Human enzymes in green
10
Hexokinase
11
Phosphohexose Isomerase
12
Phosphofructokinase-1 (PFK-1)
13
Fructose-1,6-bisphosphate Aldolase
14
Keep Track of those Carbons!
EOC Problem 9..checks out the carbons from
triose-phoshpates! Think about the aldolase ?G.
15
TIM
16
3-P-Gyld DH
EOC Problem 14 is about arsenic poisoning and
what happens when arsenate is involved with this
reaction.
17
3-PGA Kinase
18
3-PGA Mutase
19
Enolase is a Dehydrase
20
Pyruvate Kinase
21
A Fun Homework Problem

• Add up all the ?Go s and see how
• Aldolases endergonic ?G is over come.
• Total for Glycolysiswhat enzymes are doing the
  work?
• But, is that allwhat about REALITY?

EOC Problem 10 A look at modifying Glycolysis,
could it work?
22
The Real ?G
23
Showed cancer cells had high rate of glycolysis,
first to crystalize most glycolytic enzymes.
Devised the first reliable, quantitative O2
uptake apparatus, lovingly called a Warburg!..but
replaced by oxygen electrodes. Nobel Prize,
1931 and trained 6 future Nobel Laureates!! One
of which is Hans Krebs who worked out the Citric
Acid Cycle.
24
Medical Aspect CANCER
Most tumors Glycolysis goes 10X faster than
normal cells. And is mainly fermentative
(producing lactic acid). The strategy is
to 1. Use this in Detection 2. To slow
glycolysis down in cancer cells.
25
Hypoxia Induced Transcription Factor
26
Use of 6-Phospho-FdG in Positron Emission
Tomography, it accumulates in regions of high
glycolytic activity See next slide
27
CT and PET Scans
Patient with malignant melanoma ingested
6-Phospho-FdG Left-CT scan shows location of
bone, soft tissue Center-PET scan showing high
glucose use. Natural areas of high glucose use
brain but not bladder
Cancer has spread to liver, muscle Right
false color composite
28
Type 1 Diabetes and Glycolysis
29
Entry of other Sugars
30
Glycogen Phosphorylase
31
Entry of other Sugars
32
(No Transcript)
33
(No Transcript)
34
Conversion of Pyruvate to Something Else
35
Lactate DH
36
Why Lactate DH? Consider the Outputs of
Catabolism and Needs of Anabolism !
Lactate DH
37
Alligators do not have a great Cori Cycle
38
Alcohol Fermentation
EOC Problem 4 Calculating the Keq of Alcohol
Dehydrogenase (use Table 13-7) EOC Problem 6
follow the carbons from glucose into ethanol.
39
(No Transcript)
40
(No Transcript)
41
Entry of Glycerol into Glycolysis
42
Energetics of Glycerol as An Energy Source
Glycerol kinase - ATP Glycerol-3-P DH
NADH 3-P-Gyld DH NADH 3-PGA Kinase ATP Pyr
Kinase ATP Total 1 ATP 2 NADH
Can GLYCEROL be FERMENTED? Explain
43
Commercial Ethanol Fermentation
EOC Problem 7all about the heat released from
fermentationwhats going on?
44
Things to Know and Do Before Class

1. Each glycolytic reaction substrates/products,
   enzyme name, ?Gs.
2. Keep track of the carbon numbers from glucose to
   pyruvate.
3. Overall glycolytic ?G.
4. Getting other sugars and glycerol into
   glycolysis.
5. EOC Problems 1, 2, 4-7, 9, 10, 14.