Recognition of aminoglycoside antibiotics by enterococcal-staphylococcal aminoglycoside 3'-phosphotransferase type IIIa: role of substrate amino groups.

The interactions of the aminoglycoside 3'-phosphotransferase IIIa with aminoglycoside antibiotics lacking specific amino groups were examined by steady-state kinetic analyses. The results demonstrate that an amino group on C-1 and either an amino or a hydroxyl group at the 2' and 6' positions are important for detoxification of aminoglycosides by this enzyme.