preferred_name: (2S)-2-isopropylmalate => (2R,3S)-3-isopropylmalate
preferred_name_lc: (2s)-2-isopropylmalate => (2r,3s)-3-isopropylmalate
label: (2S)-2-isopropylmalate => (2R,3S)-3-isopropylmalate
label_lc: (2s)-2-isopropylmalate => (2r,3s)-3-isopropylmalate