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.
ATP FORMATION IN THE CATABOLISM OF GLUCOSE (malate shuttle)
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 osphofructokinase -2
Net 7
Citric acid cycle Pyruvate dehydrogenase Respiratory chain oxidation of 2NADH Respiratory chain oxidation of 2NADH
Isocitrate dehydrogenase Respiratory chain oxidation of 2NADH 5
a-Ketoglutaratedehydrogenase Respiratory chain oxidation of 2NADH 5
Succinate thiokinase Substrate level phosphorylation 2
Succinate dehydrogenase Respiratory chain oxidation of 2FADH2 3
Malate dehydrogenase Respiratory chain oxidation of 2NADH 5
Net 25
Total per mot of glucose under aerobic conditions 32
Total per mot of glucose under anaerobic conditions
Exam Question
  • Glycolysis is associated with the malate shuttle
Don't Forget to Solve all the previous Year Question asked on Malate Shuttle