draw out the expected step-wise reaction mechanism. predict the step that you would expect to be most effectively stabilized along the reaction pathway by the enzyme and briefly explain why. are both of the potential hydride donors hs and hr of the nadh equivalent? briefly explain why or why not. would you expect the lactate (2-hydroxy propanoic acid) formed as a product of this reaction to be optically active? briefly justify your answer. draw the complete structure of the oxidized form of nicotine amide dinucleotide (nad ).