Resveratrol activates human SIRT1 but not other Sir2 homologs. The study investigated the molecular mechanism of resveratrol activation of SIRT1. It was found that resveratrol activates SIRT1 by 8-fold, but not SIRT2 or yeast Sir2. The activation requires the presence of a fluorophore covalently attached to the peptide substrate. The fluorophore decreases the binding affinity of the peptide, and in the presence of resveratrol, fluorophore-containing substrates bind more tightly to SIRT1. A model of SIRT1 bound to p53-AMC peptide was constructed, showing that resveratrol binding promotes a conformational change that better accommodates the attached coumarin group. The study also showed that the peptide sequence is not essential for resveratrol activation, but the covalent attachment of the fluorophore is necessary. The results suggest that resveratrol induces a conformational change in SIRT1 that allows tighter binding of the fluorophore. The study used various assays, including fluorescence, charcoal binding, and HPLC, to confirm the findings. The results indicate that resveratrol activates SIRT1 by increasing its affinity for fluorophore-containing substrates. The study also showed that resveratrol does not activate the Developer II solution, indicating that the observed activation is due to the interaction with SIRT1. The study concludes that resveratrol activates SIRT1 by inducing a conformational change that allows tighter binding of the fluorophore. The findings have implications for the use of resveratrol as an activator of Sir2 homologs in various organisms.Resveratrol activates human SIRT1 but not other Sir2 homologs. The study investigated the molecular mechanism of resveratrol activation of SIRT1. It was found that resveratrol activates SIRT1 by 8-fold, but not SIRT2 or yeast Sir2. The activation requires the presence of a fluorophore covalently attached to the peptide substrate. The fluorophore decreases the binding affinity of the peptide, and in the presence of resveratrol, fluorophore-containing substrates bind more tightly to SIRT1. A model of SIRT1 bound to p53-AMC peptide was constructed, showing that resveratrol binding promotes a conformational change that better accommodates the attached coumarin group. The study also showed that the peptide sequence is not essential for resveratrol activation, but the covalent attachment of the fluorophore is necessary. The results suggest that resveratrol induces a conformational change in SIRT1 that allows tighter binding of the fluorophore. The study used various assays, including fluorescence, charcoal binding, and HPLC, to confirm the findings. The results indicate that resveratrol activates SIRT1 by increasing its affinity for fluorophore-containing substrates. The study also showed that resveratrol does not activate the Developer II solution, indicating that the observed activation is due to the interaction with SIRT1. The study concludes that resveratrol activates SIRT1 by inducing a conformational change that allows tighter binding of the fluorophore. The findings have implications for the use of resveratrol as an activator of Sir2 homologs in various organisms.