a gentamycin + GTP => a gentamycin 2''-phosphate + GDP + H(+)
a gentamycin + gtp => a gentamycin 2''-phosphate + gdp + h(+)
a gentamycin + GTP => a gentamycin 2''-phosphate + GDP + H(+)
a gentamycin + gtp => a gentamycin 2''-phosphate + gdp + h(+)