Adh requires the presence of a nicotinamide adenine dinucleotide (nad+) molecule in order to catalyze the oxidation of an alcohol. because nad+ is converted to nadh and released, it is a cosubstrate of the reaction, and nadh is a coproduct. additionally, like many enzymes, adh requires a metal cation for catalysis, which in this case is zinc (zn2+). zn2+ is not altered by adh, nor is it tightly bound to the enzyme. which term best describes the role of zn2+ in the reaction catalyzed by adh? prosthetic group cofactor cosubstrate coenzyme