a) Acetoacetate synthase catalyzes the addition of pyruvate to -ketobutyrate to yield -aceto--hydroxybutyrate. If the addition occurs from the Si face of -ketobutyrate, what is the stereochemistry of the product?

b) According to stereochemistry, how is the previous reaction defined? Explain your answer.

c) Given that the productivity number (PN) of a biocatalysed reaction is 20, what is the minimum mass of catalytic enzyme required in order to produce 50 Kg of product in 24h. Suggest why it is more advantageous to use biocatalysts with much higher PN.