A new paper entitled ‘Substrate Electronics Dominate the Rate of Reductive Dehalogenation Promoted by the Flavin-Dependent Iodotyrosine Deiodinase’ by former lab member Anton Kozyryev, current lab member Daniel Lemen and past rotation student Jessica Dunn has been published in Biochemistry! This paper probes the mechanism of iodotyrosine deiodinase through use of kinetic isotope effects, flavin cofactor analogues and iodotyrosine substrate analogues. It was found that a the substrate electronics play a large role in the rate of catalysis, suggesting the stabilization of an electrophilic intermediate in the mechanism is key for catalysis. Check it out at https://doi.org/10.1021/acs.biochem.3c00041