Question - Pyruvate carboxylase catalyzes the carboxylation of pyruvate to give oxaloacetate. This pyruvate carboxylase reaction requires the coenzyme biotin, which is the prosthetic group of the enzyme. Draw a detailed and reasonable electron-pushing mechanism for the pyruvate carboxylase reaction that accounts for the formation of all products. Invoke generic acids and bases (A-H and B:, respectively), as necessary. Also draw the fused ring structure of biotin as part of your answer.