Chemiosmotic mechanism Oxidation-reduction processes involve the transfer of electrons. Dehydrogenation is also an oxidation reaction. Addition of a hydrogen atom is also a reduction reaction. FADH 2 Enzymes are proteins that act as catalysts for chemical reactions. Almost all reactions occurring in the cell occur via the activity of enzymes.
Enzymes lower the energy barrier for a reaction to occur.
In order for a reaction to occur, the reactant molecules must combine with sufficient energy and in the proper geometry. Enzymes provide for the proper geometry of reaction by having an active site on which the reaction occurs. Characteristics of enzymes. Enzymes are proteins but not all proteins are enzymes. Enzymes may be used many times, they have a high turnover rate.