Guanine-13C5,15N5 is 13C and 15N-labeled Guanine (HY-Y1055). Guanine is one of the fundamental components of nucleic acids (DNA and RNA). Guanine is a purine derivative, consisting of a fused pyrimidine-imidazole ring system with conjugated double bonds. Guanine has the potential to serve as a large-capacity N pool. Guanine has cytotoxic, antinociceptive and neuroprotective effects[1][2][3][4].