UQCRQ Human

Ubiquinol-Cytochrome C Reductase, also known as Complex III or Cytochrome b-c1 complex, is a crucial component of the mitochondrial electron transport chain. This enzyme complex plays a pivotal role in cellular respiration, facilitating the transfer of electrons from ubiquinol to cytochrome c, which ultimately contributes to the production of ATP, the primary energy currency of the cell.

Ubiquinol-Cytochrome C Reductase is a multisubunit transmembrane complex located in the inner mitochondrial membrane. It consists of several subunits, including core proteins such as UQCRC1 and UQCRC2. The human recombinant form of this enzyme is produced through recombinant DNA technology, allowing for the study and utilization of this complex in various research and therapeutic applications.

The primary function of Ubiquinol-Cytochrome C Reductase is to facilitate the transfer of electrons within the mitochondrial electron transport chain. This process is essential for oxidative phosphorylation, where the energy derived from electron transfer is used to pump protons across the inner mitochondrial membrane, creating an electrochemical gradient. This gradient drives the synthesis of ATP by ATP synthase.

The enzyme complex operates by accepting electrons from ubiquinol (reduced form of coenzyme Q) and transferring them to cytochrome c. This electron transfer is coupled with the translocation of protons from the mitochondrial matrix to the intermembrane space, contributing to the proton motive force required for ATP synthesis. The overall reaction can be summarized as follows:

[ \text{Ubiquinol} + 2 \text{Cytochrome c (oxidized)} + 2 \text{H}^+{\text{matrix}} \rightarrow \text{Ubiquinone} + 2 \text{Cytochrome c (reduced)} + 4 \text{H}^+{\text{intermembrane space}} ]

Defects in Ubiquinol-Cytochrome C Reductase can lead to mitochondrial disorders, which are often characterized by impaired energy production. One such disorder is mitochondrial complex III deficiency, which can result in a range of symptoms including muscle weakness, neurological deficits, and metabolic abnormalities. Understanding the structure and function of this enzyme complex is crucial for developing therapeutic strategies to address these conditions.

The human recombinant form of Ubiquinol-Cytochrome C Reductase is widely used in research to study mitochondrial function and pathology. It serves as a valuable tool for investigating the mechanisms of electron transport and oxidative phosphorylation. Additionally, it has potential applications in drug development, particularly in the design of therapies targeting mitochondrial dysfunction.