label: (4,5-dihydro-5-oxofuran-2-yl)-acetate + CO2 => (R)-2-(carboxymethyl)-5-oxo-2,5-dihydro-2-furoate + H(+)
label_lc: (4,5-dihydro-5-oxofuran-2-yl)-acetate + co2 => (r)-2-(carboxymethyl)-5-oxo-2,5-dihydro-2-furoate + h(+)