What is the first compound produced in Krebs cycle?

The first compound produced in the Krebs cycle is citrate (citric acid). This occurs when acetyl-CoA (2-carbon compound) condenses with oxaloacetate (4-carbon compound) in a reaction catalyzed by citrate synthase, forming the 6-carbon citrate molecule. Citrate then undergoes isomerization and successive oxidation reactions throughout the cycle.