Malate-Aspartate Shuttle (NADH+H+)

Where is the Malate-Aspartate Shuttle prominent

Prominent in heart and liver tissue

Step 1

NADH+H + is oxidized to NAD + while oxaloacetate is reduced to malate by Cytoplasmic Malate Dehydrogenase

Step 2

Malate can traverse the inner mitochondrial membrane via Malate-α- ketoglutarate Antiporter; Malate goes in and α-ketoglutarate goes out

Step 3

Malate (now in the mitochondrial matrix) is oxidized back to oxaloacetate as NAD + is reduced to NADH+H + by Mitochondrial Malate Dehydrogenase

What needs to happen for the shuttle to continue working

α-ketoglutarate must be present in the matrix and oxaloacetate must be present in the cytoplasm

Step 4

Mitochondrial Aspartate Aminotransferase – transfers an amine group from glutamate (C5) to oxaloacetate (C4) to produce aspartate (C4) and α-ketoglutarate

Step 5

Aspartate is shuttled out to the cytoplasm via the Glutamate-Aspartate Antiporter; aspartate goes out and glutamate goes in

Step 6

Cytoplasmic Aspartate Aminotransferase - transfers an amine group from aspartate (C4) and α-ketoglutarate (C5) to produce glutamate (C5) to oxaloacetate (C4) to produce, reaction below moving left-to-right