It is likely that the substrate cysteine is deprotonated upon binding to the enzyme, but the resulting zinc-thiolate bond is so strong (due to the greater positive charge in the zinc ion) that the thi...It is likely that the substrate cysteine is deprotonated upon binding to the enzyme, but the resulting zinc-thiolate bond is so strong (due to the greater positive charge in the zinc ion) that the thiolate is unable to break away and attack the electrophilic carbon of the farnesyl diphosphate substrate.
