Malate Shuttle
INTRODUCTION:
- Mallate shuttle is a system by which reducing equivalents (NADH) produced in glycolysis are transferred from cytosol to mitochondria to yield energy.
- NADH produced in the glycolysis, is extramitochondrial where as the electron transport chain, where NADH has to be oxidized to NAD+ is in the mitochondria (Oxidation of 1 NADH yields 3 ATP/2.5 ATP). NADH is impermeable to mitochondrial membrane, so to enable transfer of NADH inside mitochondria Shuttle system is utilized.
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ATP FORMATION IN THE CATABOLISM OF GLUCOSE (malate shuttle) |
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|
Pathway |
Reaction Catalyzed by |
Method of ATP Formation |
ATP per Mol of Glucose |
| Glycolysis | Glyceraldehyde 3- phosphate dehydrogenase | Respiratory chain oxidation of 2 NADH | 5 |
| Phosphoglycerate kinase | Substrate level phosphorylation | 2 | |
| Pyruvate kinase | Substrate level phosphorylation | 2 | |
| 9 | |||
| Consumption of ATP for reactions of hexokinase and Phosphofructokinase | -2 | ||
| Net 7 | |||
| Citric acid cycle | Pyruvate dehydrogenase | Respiratory chain oxidation of 2
NADH |
5 |
| Isocitrate dehydrogenase | Respiratory chain oxidation of 2
NADH |
5 | |
| a-Ketoglutarate
dehydrogenase |
Respiratory chain oxidation of 2
NADH |
5 | |
| Succinate thiokinase | Substrate level phosphorylation | 2 | |
| Succinate dehydrogenase | Respiratory chain oxidation of 2
FADH2 |
3 | |
| Malate dehydrogenase | Respiratory chain oxidation of 2
NADH |
5 | |
| Net 25 | |||
| Total per mot of glucose under aerobic conditions | 32 | ||
| Total per mot of glucose under anaerobic conditions | |||
Exam Important
Glycolysis is associated with the malate shuttle
Don’t Forget to Solve all the previous Year Question asked on Malate Shuttle
