In the context of enzyme activity, what do coenzymes do?

Coenzymes play a crucial role in enzyme activity by participating directly in enzyme-substrate reactions. They are organic molecules that often act as carriers for functional groups, electrons, or atoms. When an enzyme catalyzes a reaction, coenzymes bind to the enzyme or substrate and assist in the transformation of the substrate to product.

For instance, many coenzymes, such as NAD+ or FAD, are involved in oxidation-reduction reactions where they accept or donate electrons. This participation is essential for the enzyme to function correctly, as the coenzyme can help stabilize the transition state or assist in the chemical changes needed during the reaction. Thus, their involvement is key in enabling many biochemical pathways to proceed efficiently and effectively.

While other aspects of enzyme function, such as substrate binding or changes in enzyme shape, are relevant, the defining characteristic of coenzymes is their role in facilitating the actual chemical reaction rather than merely altering substrate binding or enzyme structure. They do not function as inhibitors, which would obstruct or slow down enzyme activity, contrasting their supportive and enabling role in enzymatic processes.