Probably involved in the uptake of galactarate and/or D-glucarate (By similarity). May also transport D-glycerate (By similarity). galactarate(in) + H(+)(in) = galactarate(out) + H(+)(out) D-glucarate(in) + H(+)(in) = D-glucarate(out) + H(+)(out) (R)-glycerate(in) + H(+)(in) = (R)-glycerate(out) + H(+)(out) Belongs to the major facilitator superfamily. Phthalate permease family.