NOXase

NOXase is a family of enzymes that catalyze the production of reactive oxygen species (ROS), primarily superoxide anions. These enzymes are characterized by their requirement for a reduced nicotinamide adenine dinucleotide (NADH) or nicotinamide adenine dinucleotide phosphate (NADPH) as a substrate and the presence of at least two transmembrane domains. NOXases are membrane-bound proteins, typically located in the plasma membrane or internal organelle membranes.

The catalytic mechanism involves the transfer of electrons from the cofactor to molecular oxygen, forming superoxide. This process is crucial for various physiological and pathological functions. In mammals, NOX enzymes play roles in immune defense, where superoxide generated by phagocytic cells helps kill pathogens. They are also involved in cell signaling, cellular differentiation, and the regulation of vascular tone.

However, dysregulation of NOXase activity has been linked to several diseases. Excessive ROS production by NOX enzymes can lead to oxidative stress, contributing to conditions such as cardiovascular disease, cancer, inflammatory disorders, and neurodegenerative diseases. Conversely, mutations in NOX genes can result in impaired ROS production, leading to specific genetic disorders. Research into NOXases continues to explore their diverse roles and potential as therapeutic targets.