CYB5R2 Human

Cytochrome B5 Reductase 2 (CYB5R2) is an enzyme that plays a crucial role in the electron transport chain, specifically in the reduction of cytochrome b5. This enzyme is part of the larger cytochrome b5 reductase family, which is involved in various biochemical processes, including fatty acid desaturation and elongation, cholesterol biosynthesis, and drug metabolism .

CYB5R2 is a NADH-dependent enzyme that catalyzes the reduction of ferricytochrome b5 (Fe3+) to ferrocytochrome b5 (Fe2+). This reaction is essential for the proper functioning of the electron transport chain, as it facilitates the transfer of electrons from NADH to cytochrome b5. The enzyme contains flavin adenine dinucleotide (FAD) as a cofactor, which is crucial for its catalytic activity .

The overall reaction catalyzed by CYB5R2 can be summarized as follows:

$$\text{NADH} + \text{H}^+ + 2 \text{ferricytochrome b5} \rightarrow \text{NAD}^+ + 2 \text{ferrocytochrome b5}$$

CYB5R2 is involved in several critical biochemical pathways. It plays a significant role in the desaturation and elongation of fatty acids, which are essential for maintaining cell membrane integrity and fluidity. Additionally, CYB5R2 is involved in cholesterol biosynthesis, a vital process for the production of steroid hormones and bile acids .

Moreover, CYB5R2 is implicated in drug metabolism, where it helps in the detoxification of various xenobiotics and drugs. This enzyme’s ability to reduce methemoglobin to hemoglobin is particularly important in erythrocytes, where it helps maintain the proper function of red blood cells .

Recombinant CYB5R2 refers to the enzyme produced through recombinant DNA technology. This involves inserting the gene encoding CYB5R2 into a suitable expression system, such as bacteria or yeast, to produce the enzyme in large quantities. Recombinant CYB5R2 is used in various research applications to study its structure, function, and role in different biochemical pathways.

Mutations in the CYB5R2 gene can lead to various metabolic disorders. For instance, deficiencies in cytochrome b5 reductase activity can result in methemoglobinemia, a condition characterized by an increased level of methemoglobin in the blood, leading to reduced oxygen delivery to tissues . Understanding the structure and function of CYB5R2 is crucial for developing therapeutic strategies to treat such conditions.