[realvirtuality]

Many enzymes catalyze reactions that are similar to reactions that we might use for organic synthesis. Enzymes tend to be stereospecific in their reactions. The following reaction, part of the TCA cycle of cell respiration, resembles a reaction we might use in the laboratory; however, the enzyme-catalyzed reaction gives only the (S) enantiomer of the product, malic acid.

a. What type of reactions does fumarase catalyze?
b. If we could run the preceding reaction in the laboratory using sulfuric acid as the catalyst, would the product (malic acid) be optically active?
c. Do you expect the fumarase enzyme to be a chiral molecule?
d. When the enzyme-catalyzed reactions takes place in D₂O, the only product is the stereoisomer pictured. No enantiomer or diastereomer of this compound is formed. Is the enzyme-catalyzed reaction a syn or anti addition?
e. Assume that we found conditions to convert fumaric acid to deuterated malic acid using hydroboration with BD₃·THF, followed by oxidatino with D₂O₂ and NaOD. use Fischer projections to show the stereoisomer(s) of deuterated malic acid you would expect to be formed.

Here are my answers of the ones I think I got:
a. Hydration reaction
c. Fumarase enzyme would be an achiral molecule.
d. Syn addition?

Thank you in advance!