succinate(out) + 2 H(+)(out) => succinate(in) + 2 H(+)(in)
succinate(out) + 2 h(+)(out) => succinate(in) + 2 h(+)(in)
succinate(out) + 2 H(+)(out) => succinate(in) + 2 H(+)(in)
succinate(out) + 2 h(+)(out) => succinate(in) + 2 h(+)(in)