1. tell me the enzyme mechanism/biosynthetic pathway 2. tell me what it happening in each step. You can use words like "activating nucleophiles, stabilizing intermediates, positioning substrates (holding stuff), transferring protons, facilitating leaving groups." You are not allowed to use a protease or nuclease (or ribonuclease) or esterase (lipase). If you pick an enzyme with a metal chances are there is also redox occurring. In that case, where are the oxidation/reduction steps? E72 H 196.