What are cofactors in biochemical systems?

Cofactors are essential components in biochemical systems that facilitate various biochemical reactions. They are typically defined as non-protein molecules or ions that bind to enzymes and help them catalyze reactions more effectively. In this context, non-protein metal ions, such as zinc, magnesium, and iron, play a critical role by stabilizing enzyme structures, participating directly in the catalytic process, or helping to form the enzyme-substrate complex.

In contrast to the focus on non-protein metal ions, proteins that inhibit enzymatic activity or substances like vitamins that provide energy, do not fit the definition of cofactors. Vitamins, while they may be involved in various metabolic processes, often act as precursors to coenzymes rather than serving directly as cofactors themselves. Simple sugars, while important for energy metabolism, do not function as cofactors. Therefore, the identification of cofactors as non-protein metal ions that assist proteins emphasizes their role in enhancing enzymatic activity and facilitating biochemical pathways.