1 GUN Guanine 1.000 2 8IG 8-iodo-guanine 0.917 3 9MG 9-methylguanine 0.917 4 ANG 8-aminoguanine 0.917 5 B55 2-amino-8-sulfanyl-1,9-dihydro-6h-purin-6-one 0.917 6 BRG 8-bromoguanine 0.917 7 MY6 2-amino-7-methyl-1,7-dihydro-6h-purin-6-one 0.917 8 OXG 8-oxoguanine 0.917 9 2BP 9h-purin-2-amine 0.909 10 HPA Hypoxanthine 0.909 11 NDM 7,9-dimethylguanine 0.846 12 2ON 2-sulfanyl-1,9-dihydro-6h-purin-6-one 0.833 13 6AP 9h-purine-2,6-diamine 0.833 14 6GU 6-chloroguanine 0.833 15 7DG 7-deazaguanine 0.833 16 9DG 9-deazaguanine 0.833 17 AZG 5-amino-1h-[1,2,3]triazolo[4,5-D]pyrimidin-7-ol 0.833 18 BOA 2-bromo-6-hydroxy-purine 0.833 19 DX4 2-amino-1,9-dihydro-6h-purine-6-thione 0.833 20 HH5 6-iodanyl-7~{H}-purin-2-amine 0.833 21 QY8 2-amino-3h,4h,7h-pyrrolo[2,3-D]pyrimidin-4-one 0.833 22 XAN Xanthine 0.833 23 29H 2-aminopyrimido[4,5-D]pyrimidin-4(3h)-one 0.769 24 5JL 2,8-dithioxo-1,2,3,7,8,9-hexahydro-6h-purin-6-one 0.769 25 5JQ 2-thioxo-2,3,7,9-tetrahydro-1h-purine-6,8-dione 0.769 26 6GO 6-O-methylguanine 0.769 27 8HX 8-hydroxy-3,9-dihydro-1h-purine-2,6-dione 0.769 28 8TX 8-thioxo-3,7,8,9-tetrahydro-1h-purine-2,6-dione 0.769 29 FDB 2-amino-5-methyl-3h-pyrrolo[2,3-D]pyrimidin-4(7h)-one 0.769 30 MOG 5-amino-2-methyl-6h-oxazolo[5,4-D]pyrimidin-7-one 0.769 31 PE0 Pterine 0.769 32 QBK 5-azanyl-[1,3]thiazolo[5,4-D]pyrimidine-2,7-dione 0.769 33 T0A 5-deazatetrahydropterin 0.769 34 URC Uric acid 0.769 35 W5M 9-methyl-9h-purine-2,6-diamine 0.769 36 6MP 6-methylpurine 0.750 37 7HX 7h-pyrrolo[2,3-D]pyrimidin-4-ol 0.750 38 9HX 9-deazahypoxanthine 0.750 39 ADE Adenine 0.750 40 BP1 6-bromo-7h-purine 0.750 41 ES4 6-chloro-9h-purine 0.750 42 PM6 9h-purine-6-thiol 0.750 43 GSY 7-(2-hydroxyethyl)-8-mercaptoguanine 0.733 44 28Y 3h-imidazo[2,1-B]purin-4(5h)-one 0.714 45 37T Theobromine 0.714 46 44V (6s)-2-amino-6-methyl-5,6,7,8-tetrahydropteridin-4(3h)-one 0.714 47 44W 2-amino-6-methyl-7,8-dihydropteridin-4(3h)-one 0.714 48 7PD 2-aminopteridine-4,7(3h,8h)-dione 0.714 49 B60 2-amino-8-methyl-7,8-dihydropteridin-4(3h)-one 0.714 50 B62 (6r)-2-amino-6-methyl-5,6,7,8-tetrahydropteridin-4(3h)-one 0.714 51 GD1 2-amino-5-[(z)-iminomethyl]-3,7-dihydro-4h-pyrrolo[2,3-D]pyrimidin-4-one 0.714 52 HNG 2-amino-5-(aminomethyl)-1,7-dihydro-4h-pyrrolo[2,3-D]pyrimidin-4-one 0.714 53 JSO 2-azanyl-6-methyl-3~{H}-pteridin-4-one 0.714 54 MUA 9-methyl uric acid 0.714 55 PQ0 2-amino-4-oxo-4,7-dihydro-3h-pyrrolo[2,3-D]pyrimidine-5-carbonitrile 0.714 56 PRF 7-deaza-7-aminomethyl-guanine 0.714 57 TEP Theophylline 0.714 58 UAN 9-methyl-2-(methylamino)-1h-purin-6-one 0.714 59 XHP 2-amino-6-methylidene-6,7-dihydropteridin-4(3h)-one 0.714 60 XTN 2-amino-1,5-dihydropteridine-4,6-dione 0.714