oksidoreduktase

Oxidoreductases are a class of enzymes that catalyze oxidation-reduction (redox) reactions, facilitating the transfer of electrons between molecules. These reactions are fundamental to metabolism, energy production, and biosynthesis in living organisms. Oxidoreductases are classified under Enzyme Commission (EC) number 1, the largest group of enzymes, and are defined by their role in transferring hydrogen or electrons from one substrate (the reductant or donor) to another (the oxidant or acceptor).

The general reaction catalyzed by oxidoreductases can be represented as:

Donor – H + acceptor → donor + acceptor – H

or, in terms of electron transfer:

Donor + acceptor → oxidized donor + reduced acceptor

These enzymes are essential in various biochemical pathways, including glycolysis, the citric acid cycle, and electron transport chains. For example, dehydrogenases, a subclass of oxidoreductases, remove hydrogen atoms from substrates, often converting them into their oxidized forms while reducing a coenzyme like NAD⁺ to NADH or FAD to FADH₂. Other examples include oxidases, which transfer electrons to molecular oxygen, and peroxididases, which use hydrogen peroxide as an electron acceptor.

Oxidoreductases often require cofactors such as metal ions (e.g., iron, copper) or organic molecules (e.g., flavins, quinones) to facilitate electron transfer. Some, like cytochrome P450 enzymes, play critical roles in drug metabolism and steroid biosynthesis. Their specificity varies, with some acting on broad substrate ranges while others are highly selective.

Deficiencies or dysfunctions in oxidoreductase activity can lead to metabolic disorders, affecting energy production or detoxification processes. Research into these enzymes continues to inform fields like biotechnology, medicine, and environmental science, particularly in developing enzymatic catalysts for sustainable industrial processes.