What is the function of oxidoreductase enzymes


English: oxidoreductase

1 definition

Under the term Oxidoreductases summarizes a group of enzymes that catalyze redox reactions.

2 Classification of oxidoreductases

The oxidoreductases are divided into five groups.

2.1 Oxidases

Oxidases catalyze reactions in which hydrogen is transferred from a substrate to oxygen. This creates hydrogen peroxide.

Examples of oxidases:

2.2 oxygenases

2.2.1 Monooxygenases

Monooxygenases work with molecular oxygen and transfer an oxygen atom to a substrate. The other oxygen atom is transferred to hydrogen coming from a hydrogen donor, so that water is created.

Examples of monooxygenases:

2.2.2 Dioxygenases

Dioxygenases transfer molecular oxygen to a substrate.

Example for dioxygenases:

2.3 Hydroperoxidases

2.3.1 Catalase

The catalase catalyzes the reaction of two molecules of hydrogen peroxide to oxygen and two molecules of water and is thus involved in the breakdown of reactive oxygen species. She needs heme iron.

2.3.2 Peroxidase

The peroxidase transfers hydrogen to hydrogen peroxide, creating two molecules of water. Peroxidase also needs heme iron.

2.4 dehydrogenases

2.4.1 Anaerobic dehydrogenases

The anaerobic dehydrogenases are divided into three groups. NAD / NADP-dependent dehydrogenases

These dehydrogenases transfer hydrogen from a substrate to NAD + or NADP +, so that NADH + H + or NADPH + H + and the oxidized substrate are formed.

Examples of NAD / NADP-dependent dehydrogenases: FAD-dependent dehydrogenases

The FAD-dependent dehydrogenases transfer hydrogen from a substrate to FAD. This results in reduced FAD and the oxidized substrate.

Examples of FAD-dependent dehydrogenases: Cytochrome-dependent dehydrogenases

These dehydrogenases catalyze the splitting of hydrogen bound to the substrate into two hydrogen ions and two electrons, with the electrons being transferred to the iron (III) ion, which is located in the cytochrome. The oxidized substrate, two hydrogen ions and two iron (II) ions are created.

Example of cytochrome-dependent dehydrogenases:

2.4.2 Aerobic dehydrogenases

The aerobic dehydrogenases catalyze reactions in which hydrogen is transferred from a substrate to an oxidized acceptor, the oxidized substrate and the reduced acceptor being formed. In a subsequent reaction, the hydrogen is transferred from the acceptor to oxygen. The products of this reaction are water and the oxidized acceptor.

Examples of aerobic dehydrogenases: