guanosine(out) + H(+)(out) => guanosine(in) + H(+)(in)
guanosine(out) + h(+)(out) => guanosine(in) + h(+)(in)
guanosine(out) + H(+)(out) => guanosine(in) + H(+)(in)
guanosine(out) + h(+)(out) => guanosine(in) + h(+)(in)