In which step do you find the conversion of L-Malate to Oxaloacetate?

The conversion of L-Malate to Oxaloacetate occurs in a specific enzymatic reaction facilitated by malate dehydrogenase, which is part of the citric acid cycle (Krebs cycle). This reaction is significant because it represents the final step of the cycle where malate is oxidized while NAD+ is reduced to NADH.

In this step, L-Malate, a four-carbon compound, is oxidized to form Oxaloacetate, which is also a four-carbon compound. The reduction of NAD+ to NADH during this process is an essential part of cellular respiration, as it contributes to the electron transport chain and ATP production.

Understanding the placement of this reaction in the citric acid cycle is crucial because it highlights the cycle's role in not only the production of energy but also the regeneration of Oxaloacetate, allowing the cycle to continue with the next acetyl-CoA entering the pathway. This maintains the continuity of the cycle, making the conversion of L-Malate to Oxaloacetate an essential part of metabolic processes in aerobic organisms.