Cofactors and coenzymes play vital roles in enhancing the catalytic activity of enzymes by supplying essential functional groups or facilitating substrate binding.

Cofactors are non-protein molecules that associate with enzymes to aid in the catalytic process. These molecules can be classified as either inorganic, such as metal ions, or organic, such as heme. Inorganic cofactors typically function as electron carriers, while organic cofactors often provide the functional groups necessary for catalysis. A notable example is biotin, a cofactor essential for the carboxylation of pyruvate during gluconeogenesis.

Coenzymes, on the other hand, are organic molecules required for enzyme activity but are not permanently attached to the enzyme. They frequently serve as carriers of functional groups or electrons. Examples include NAD$^+$ and FAD, which transport electrons in redox reactions. Additionally, coenzymes can assist in substrate binding; for instance, ATP acts as a coenzyme that helps enzymes effectively connect with their substrates.

In summary, both cofactors and coenzymes are crucial for enzyme-catalyzed reactions. They provide necessary functional groups and facilitate substrate binding, ensuring that many biochemical reactions occur efficiently. Without these important molecules, the functionality of many enzymes would be significantly impaired, if not entirely hindered.