NADH oxidase is an enzyme that plays a crucial role in cellular respiration by catalyzing the oxidation of NADH to NAD+. This process is essential for generating energy in the form of ATP within cells. NADH oxidase is found in various organisms, including bacteria and mitochondria, where it helps maintain the balance of NADH and NAD+. The enzyme functions by transferring electrons from NADH to molecular oxygen, producing NAD+ and reactive oxygen species as byproducts. This reaction is vital for metabolic processes and contributes to the overall energy production in cells, supporting various biological functions.