The aminoglycoside phosphotransferases achieve inactivation of their antibiotic substrates by phosphorylation utilising ATP. Likewise hydroxyurea is inactivated by phosphorylation of the hydroxy group in the hydroxylamine moiety [1,2,3].

1: Nucleotide sequence of the streptomycinphosphotransferase and amidinotransferase genes from Streptomyces griseus. Tohyama H, Okami Y, Umezawa H; Nucleic Acids Res 1987;15:1819-1833. PMID:3029728

2: Bacterial resistance to aminoglycoside antibiotics. Davies J, Wright GD; Trends Microbiol 1997;5:234-240. PMID:9211644

3: A gene (hur) from Streptomyces aureofaciens, conferring resistance to hydroxyurea, is related to genes encoding streptomycin phosphotransferase. Kormanec J, Farkasovsky M, Potuckova L, Godar S; Gene 1992;114:133-137. PMID:1316866