Apterin is primarily used in biochemical research due to its role as a precursor or analog in pteridine metabolism. It serves as a reference compound in studies involving enzyme pathways related to folate and biopterin synthesis, helping scientists understand metabolic disorders and redox processes in cells. Its structural similarity to natural pterins allows it to be used in assays investigating the activity of pterin-dependent enzymes. Additionally, Apterin has been explored in photobiological studies because of its light-absorbing properties, contributing to research on oxidative stress and cellular signaling under UV exposure. Due to its involvement in redox cycling, it also supports investigations into reactive oxygen species generation and antioxidant defense mechanisms.