preferred_name: S-methyl-L-methionine + L-selenocysteine => Se-methyl-L-selenocysteine + L-methionine + H(+)
preferred_name_lc: s-methyl-l-methionine + l-selenocysteine => se-methyl-l-selenocysteine + l-methionine + h(+)
label: S-methyl-L-methionine + L-selenocysteine => Se-methyl-L-selenocysteine + L-methionine + H(+)
label_lc: s-methyl-l-methionine + l-selenocysteine => se-methyl-l-selenocysteine + l-methionine + h(+)