Citrate synthase is an important enzyme in the Krebs cycle, also known as the citric acid cycle. It catalyzes the first step of this metabolic pathway by combining acetyl-CoA and oxaloacetate to form citrate. This reaction is crucial for energy production in cells, as it helps convert carbohydrates, fats, and proteins into usable energy. The enzyme is found in the mitochondria of eukaryotic cells and plays a key role in cellular respiration. Citrate then undergoes further transformations in the Krebs cycle, leading to the production of NADH and FADH2, which are essential for generating ATP, the energy currency of the cell.