Mitochondrial Complex I Activity Colorimetric Assay

Mitochondrial Complex I is the initiator and key rate-limiting enzyme of the respiratory chain, responsible for transferring electrons from NADH to ubiquinone, while driving proton transmembrane transport and providing the basis for ATP synthesis. Its dysfunction is closely related to various pathological processes such as neurodegenerative diseases, metabolic abnormalities, and aging. Therefore, accurate detection of complex I activity is of great significance for basic research and drug development.

Mitochondrial Complex I Activity Colorimetric Assay provides a fast and reliable method for determining the activity of mitochondrial complex I in purified mitochondria. It can be used to assess the effects of toxicants, drugs, and environmental factors on complex I function. This kit uses decylubiquinone as an electron acceptor, which is catalyzed by complex I to produce decylubiquinol. The latter then transfers electrons to Complex I Dye that absorbs light at 600 nm. Reduction of the dye results in a decrease in absorbance at 600 nm, allowing complex I activity to be quantitatively​ determined by monitoring this change. The kit also provides a complex I inhibitor, enabling the determination of specific mitochondrial complex I activity after subtracting the activity in presence of Complex I inhibitor from total activity.

Figure 1. Typical standard curve and assay data. (A) DCIP standard curve for oxidized Complex I dye, (B) the kinetic mode of varying concentrations of mitochondria