Cofaktorite

Cofaktorite, known in English as cofactors, are non-protein chemical compounds that are essential for the biological activity of some enzymes. They can be inorganic ions, such as magnesium (Mg2+) or zinc (Zn2+), or complex organic molecules called coenzymes. Cofactors bind to an enzyme, either temporarily or permanently, and are crucial for the enzyme to catalyze its specific reaction.

If a cofactor is an inorganic ion, it is often referred to as an activator. These ions can help stabilize the enzyme's structure or participate directly in the chemical reaction by facilitating electron transfer or holding substrates in the correct orientation. Without the appropriate cofactor, the enzyme may be inactive or significantly less efficient.

Coenzymes, on the other hand, are organic molecules that often act as carriers of specific atoms or functional groups. Many coenzymes are derived from vitamins. For example, NAD+ (nicotinamide adenine dinucleotide) and FAD (flavin adenine dinucleotide) are important coenzymes involved in redox reactions. They accept or donate electrons, thereby playing a vital role in metabolic pathways like cellular respiration.

The combination of an enzyme and its cofactor is called a holoenzyme. The enzyme without its cofactor is called an apoenzyme. The holoenzyme is the complete, catalytically active form of the enzyme. The interaction between the apoenzyme and its cofactor is often highly specific, ensuring that the correct reaction is catalyzed.