preferred_name: L-cystine(out) + L-leucine(in) => L-cystine(in) + L-leucine(out)
preferred_name_lc: l-cystine(out) + l-leucine(in) => l-cystine(in) + l-leucine(out)
label: L-cystine(out) + L-leucine(in) => L-cystine(in) + L-leucine(out)
label_lc: l-cystine(out) + l-leucine(in) => l-cystine(in) + l-leucine(out)