AP BIOLOGY

Detailed explanation-1: -Step 1: The first step is the condensation of acetyl CoA with 4-carbon compound oxaloacetate to form 6C citrate, coenzyme A is released. The reaction is catalysed by citrate synthase. Step 2: Citrate is converted to its isomer, isocitrate. The enzyme aconitase catalyses this reaction.

Detailed explanation-2: -Oxaloacetate to Citrate Catalyzed by Citrate Synthase Citrate synthase is a protein with 433 amino acids with various functional groups that can react with substrates. This enzyme catalyzes oxaloacetate to eventually produce citrate as part of the citric acid (Krebs) cycle.

Detailed explanation-3: -Krebs cycle starts with the formation of a six carbon compound by the reaction between oxaloacetic acid and acetyl CoA. The 6 carbon compound formed is citric acid and this reaction is catalyzed by citrate synthase.

Detailed explanation-4: -Condensation of Acetyl-CoA with Oxaloacetate to Form Citrate Formation of citrate is the committed step of the cycle and is regulated by allosteric effectors.

Detailed explanation-5: -Citrate synthase catalyzes the condensation reaction of the two-carbon acetate residue from acetyl coenzyme A and a molecule of four-carbon oxaloacetate to form the six-carbon citrate: acetyl-CoA + oxaloacetate + H2O