-!- This bacterial enzyme phosphorylates many 4,6-disubstituted aminoglycoside antibiotics that have a hydroxyl group at position 2'', including kanamycin A, kanamycin B, tobramycin, dibekacin, arbekacin, amikacin, gentamicin C, sisomicin and netilmicin. -!- In most, but not all, cases the phosphorylation confers resistance against the antibiotic. -!- Some forms of the enzyme use ATP as a phosphate donor in appreciable amount. -!- The enzyme is often found as a bifunctional enzyme that also catalyzes 6'-aminoglycoside N-acetyltransferase activity. -!- The bifunctional enzyme is the most clinically important aminoglycoside-modifying enzyme in Gram-positive bacteria, responsible for high-level resistance in both Enterococci and Staphylococci.