urea(out) + ATP + H2O <=> urea(in) + ADP + phosphate + H(+)
urea(out) + atp + h2o <=> urea(in) + adp + phosphate + h(+)
urea(out) + ATP + H2O <=> urea(in) + ADP + phosphate + H(+)
urea(out) + atp + h2o <=> urea(in) + adp + phosphate + h(+)