TY - JOUR ID - 16616 TI - Decrease of catalytic efficiency of Photinus pyralis firefly luciferase in the presence of graphene quantum dots JO - Nanomedicine Journal JA - NMJ LA - en SN - 2322-3049 AU - Samadi, Elaheh AU - Javanmardi, Masoud AU - Porzani, Samaneh Jafari AU - Hosseinkhani, Saman AD - Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran AD - Department of Medical Biotechnology, Applied Biophotonics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran AD - Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran Y1 - 2020 PY - 2020 VL - 7 IS - 4 SP - 308 EP - 314 KW - Bioluminescence KW - Graphene KW - Luciferase KW - Quantum dot DO - 10.22038/nmj.2020.07.00007 N2 - Objective(s): Firefly luciferase is a monooxygenase enzyme that emits flash of light during the enzymatic reaction. Luciferase has been used in many bioanalytical fields from ATP detection methods to in vivo imaging. In recent decades, focus has been carried out on nanoparticles for their fluorescence properties. Semiconductor quantum dots have unique tunable properties that turn them promising tools in biological and biomedical researches, as nanosensors, photo-electrochemical and light-emitting devices. Carbon-based nanoparticles such as graphene quantum dots (GQDs) have useful benefits such as low toxicity, suitable luminescence and easy preparation. Materials and Methods: In this study, recombinant P. pyralis luciferase was expressed and purified based on N-terminal His-tag and then kinetic parameters of enzyme activity such as Km and Vmax values in presence and absence of GQDs were calculated. Results: The results showed that Km for ATP and luciferin substrates in the presence of GQDs were increased. Fluorescence spectroscopy showed significant changes in protein structure or in fluorescence spectra and decrease in the activity of the luciferase in presence of GQD. Both loss of activity and increase of substrates Km showed decrease of catalytic efficiency presumably through structural alteration. Conclusion: From these data it can be concluded that the protein structure under the influence of GQD may have changed that lead to alteration of enzyme activity. UR - https://nmj.mums.ac.ir/article_16616.html L1 - https://nmj.mums.ac.ir/article_16616_8fb826a21de61aa89492dad1bd01f017.pdf ER -