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||P.1 left column top paragraph: "A large proportion of enzymes depend on organic cofactors to enlarge the biochemical potential of cellular metabolism that can be generated by proteins alone [primary source]. In fact, all enzyme classes harbour members that depend on organic cofactors, with oxidoreductases being the most prominent representative, as more than 80% of these enzymes require coenzymes such as nicotinamide adenine dinucleotide (NAD)[primary source]. Unlike most metabolites, coenzymes mainly act catalytically, and their configurations revert back to the original state, usually via a second enzymatic reaction (for example, in redox reactions). This is known as ‘catalytic turnover’ and typically occurs at a high rate."