Aminoglycoside antibiotic with a bactericidal action against most gram negative bacteria. Incorporates into sensitive bacterial cells by an active transport process. Binds to the 30S and to some extent the 50S subunits of the bacterial ribosome, inhibiting protein synthesis and generating errors in the transcription of the genetic code. Widely used as a selective agent for the incorporation of the NPT II (APH3') gene in plant tissue.