Final answer:
The malate dehydrogenase that is part of the cytosolic malate-aspartate shuttle is MDH1, which is distinct from the mitochondrial MDH2.
Step-by-step explanation:
The malate dehydrogenase (MDH) found in the cytoplasm that serves as part of the malate-aspartate shuttle is MDH1. This enzyme plays a crucial role in the transfer of reducing equivalents across the mitochondrial membrane. The malate-aspartate shuttle is vital for moving NADH, the reduced form of NAD+ produced during glycolysis, into the mitochondria where it can contribute to ATP production via the electron transport chain. Mitochondrial MDH (referred to as MDH2) lowers leaf respiration and alters plant growth, as seen in species like Arabidopsis. Furthermore, over-expression of cytosolic NAD-dependent MDH gene can lead to enhanced growth and stress tolerance in plants.