confers_resistance_to_antibiotic erythromycin confers_resistance_to_antibiotic tylosin azithromycin mgtA mgtA mgt ARO:3000462 antibiotic_resistance A macrolide glycosyltransferase encoded by the mgtA gene in Streptomyces lividans. This enzyme inactivates macrolides using UDP-glucose as a cofactor. Its optimal substrates are lankamycin, calcomycin, rosaramicin, methymycin, and pikromycin, while interactions with erythomycin, oldeandomycin, azithromycin, and tylosin were weaker. It is inactive against spiramycin and carbomycin. Mechanism first described by Cundliffe, 1992. methymycin mgt macrolide glycotransferase