The 6-carbon compound formed from oxaloacetic acid and acetate is called citrate. This reaction occurs in the citric acid cycle (also known as the Krebs cycle), a series of chemical reactions that generate energy for the cell through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins.

In the citric acid cycle, oxaloacetic acid combines with acetyl-CoA to form citrate. Citrate then undergoes a series of enzymatic reactions to produce energy-rich molecules like guanosine triphosphate (GTP) and nicotinamide adenine dinucleotide (NADH). These energy-rich molecules are vital for various cellular processes, including biosynthetic reactions and the generation of ATP, the primary energy currency of the cell.