1. Enzyme Nomanclature

2. CP and ATP Use During Exercise
Myokinase reaction 2 ADP ATP + AMP

3. - H - C - H - C - C - C - C - C = O - C - C = O - C - C = O O = C = O
methyl
H - C - H OH -
alcohol
C - C - C H -
aldehyde
C - C = O C -
keto
C - C = O
Carbon dioxide OH -
carboxylic acid
O = C = O
C - C = O

4. Glycolysis

5. Glycolysis -conversion of glucose to pyruvate, ATP & NADH + H+
ADP
ATP O O
Glucose
Glucose-6-P
(C6H12O6)
- IRREVERSIBLE (kinase reaction)--Glucokinase in liver, Hexokinase in skeletal muscle
- takes 1 ATP
- now locked in cell because phosphorylated compounds can’t cross cell membranes by diffusion and are not recognized by GLUT transporters
- Keeps intracellular free glucose levels very low to maintain facilitated diffusion gradient

6. Glycolysis (cont.) Step 2: C P P C C O O Glucose-6-P Fructose-6-P
G-6-P Isomerase
Glucose-6-P
Fructose-6-P
Isomerization (rearrangement of bonds)
-(ie Aldose
Ketose)
-frees the #1-C to be phosphorylated

7. (Phosphofructokinase (PFK)-1)
Glycolysis (cont.)
Step 3:
ATP
ADP P C C P C C P O O
(Phosphofructokinase (PFK)-1)
Fructose-6-P
Fructose-1,6-Bisphosphate
Irreversible (kinase reaction)
- takes 1 ATP (-2 so far)
- phosphorylates fructose at 1-C

8. Glycolysis (cont.) Step 4: H O H H C H C O P H C O P H C OH C O + C O
(aldolase) H H C OH H H C OH
DHAP
G-3-P H C O P
DHAP= dihydroxyacetone phosphate (3-C)
G-3-P= Glyceraldehyde 3 phosphate (3-C) H
F-1,6 BP (6-C)

9. Glycolysis (cont.) Step 5: C O P C O P H C OH C O Triose - P Isomerase
DHAP
G-3-P
Isomerization - rearrangement of Bonds
- Ketose Aldehyde
- 1 G-6-P G-3-P

10. Glycolysis (cont.) Step 6: No Energy has been gained YET! -2 ATP H O O
NAD+
NADH + H+ C C C OH C OH Pi C O P C O P
G-3-P
1, 3, D.P.G
-Phosphoglyceraldehyde dehydrogenase
-NAD+ reduced
-Aldehyde C oxidized to carboxylic acid

11. (Phosphoglycerate kinase)
Glycolysis (cont.)
Step 7: O O P O O-
ADP
ATP C C
(2x) C OH
(Phosphoglycerate kinase) C OH C O P C O P
1, 3, DPG
3 Phosphoglycerate
*1, 3 DPG has a G of (ATP = -7.3)
Substrate level phosphorylation

12. (Phosphoglycerate mutase)
Glycolysis (cont.)
Step 8: O O- O O- C C C OH
(Phosphoglycerate mutase) C O P C O P C OH
3 Phosphoglycerate
2 Phosphoglycerate
*mutase - transfers a phosphate group

13. Phosphoenol pyruvate (PEP)
Glycolysis (cont.)
Step 9: O- O O O- C
+H20 C
(Enolase) C O P C O P C OH C
2 Phosphoglycerate
Phosphoenol pyruvate (PEP)
This is a dehydration step. WHY?
G of PEP =

14. Generate 2 ATP via substrate level phosphorylation
Glycolysis (cont.)
Step 10: O O- O O- C
+H20 C
ADP
ATP C O P C O
(Pyruvate kinase) C
CH3
Pyruvate
PEP
Generate 2 ATP via substrate level phosphorylation

15. (Lactate Dehydrogenase)
Glycolysis (cont.)
step 6
Step 11: O O- O O- C C
NADH + H
NAD C O H C O H
(Lactate Dehydrogenase)
CH3
CH3
Lactate
Pyruvate
NADH + H oxidized to NAD
pyruvate reduced to lactate

16. LDH Isozymes LDH-H has a high Km for pyruvate (lactate to pyruvate)
LDH-M has a low Km for pyruvate (pyruvate to lactate)

17. Glycolysis - Summary
Step 1: ATP
Step 3: ATP
Step 6: NADH + H +
Step 7: ATP phoshoglyceraldehyde kinase
Step 10: + 2 ATP pyruvate kinase
NET
+ 2 ATP via substrate-level phosphorylation
Key regulated enzymes: PFK and HK

18. Glycolysis - Summary (cont.)
Key enzyme: PFK (step 3)
-allosterically regulated
Activated by:
- AMP, ADP, PI
Inactivated by:
- ATP
- Citrate
- H+

19. CP and ATP Use During Exercise
Myokinase reaction 2 ADP ATP + AMP

20. Glycolytic Flux with Graded Exercise
Over rest: x x x x
Over 35% VO2 max x x x

23. Cell to Cell Lactate Shuttle

27. Immunolabeling of LDH using antibodies conjugated with 15nm gold particles

29. Monocarboxylic transporter MCT 1-8 mMCT pmMCT

32. Localization of Krebs Cycle:
Glycolysis occurs in the cytosol of cells.
Pyruvate transported into the
mitochondrion to be metabolized further.
Mitochondrial Compartments:
The matrix contains Pyruvate Dehydrogenase, enzymes of Krebs Cycle, and other pathways, e.g., fatty acid oxidation & amino acid metabolism.

33. Mitochondrial compartments
Inner membrane infoldings, called cristae, contain constituents of the respiratory chain & ATP Synthase.
The inner membrane is the major permeability barrier.
It contains various transport catalysts, including a carrier protein that allows pyruvate to enter the matrix.

34. Pyruvate Dehydrogenase, catalyzes oxidative decarboxylation of pyruvate, to form acetyl-CoA.

35. Pyruvate Dehydrogenase is a large complex, with multiple copies of each of 3 enzymes:
E1, E2 & E3.

36. View an animation of the Pyruvate Dehydrogenase reaction sequence.
Acetyl CoA, a product of the Pyruvate Dehydrogenase reaction, is a central compound in metabolism.

37. Activation of PDH with Graded Exercise

38. Regulation of PDH during exercise*

40. % of CHO from:
Glycogen % % % %
Blood glucose % % % %

41. % of pyruvate into:
CAC % % % %
HLA % % % %

43. PDH activation with Graded Exercise