label: a 5'-end 2'-deoxyribose-2'-deoxyribonucleotide-DNA => (2E,4S)-4-hydroxypenten-2-al-5-phosphate + a 5'-end 5'-phospho-2'-deoxyribonucleoside-DNA + H(+)
label_lc: a 5'-end 2'-deoxyribose-2'-deoxyribonucleotide-dna => (2e,4s)-4-hydroxypenten-2-al-5-phosphate + a 5'-end 5'-phospho-2'-deoxyribonucleoside-dna + h(+)