label: L-lysyl(37)-[histone H3] + 3 S-adenosyl-L-methionine => N(6),N(6),N(6)-trimethyl-L-lysyl(37)-[histone H3] + 3 S-adenosyl-L-homocysteine + 3 H(+)
label_lc: l-lysyl(37)-[histone h3] + 3 s-adenosyl-l-methionine => n(6),n(6),n(6)-trimethyl-l-lysyl(37)-[histone h3] + 3 s-adenosyl-l-homocysteine + 3 h(+)