Properties of pyrimidines and Purines Keto- enol tautomerism(酮烯醇互变异构) Acid/ base dissociations(酸碱解离) Strong absorbance of uv light(紫外吸收)
Properties of Pyrimidines and Purines • Keto-enol tautomerism （酮-烯醇互变异构） • Acid/base dissociations （酸碱解离） • Strong absorbance of UV light （紫外吸收）
OH N N N HO H Lactam Lactim 内酰胺 内酰亚胺
内酰胺 内酰亚胺
OH N N HN N N H2N N N H Keto form Enol form
Base Tautomerization (碱基互变异构) G(Keto G(Enol) A N A2N 2N 99.999 0.01 ≡A
G (Keto) G (Enol) A 99.99% 0.01% Base Tautomerization (碱基互变异构） 5
SAMP SUMP 5'CMP 5'GMP 1.0 pH7 pH 7 oH 2 pH7 08 0.8 0.8 as 06 06 06 pH I 0.4 H H7 02 0.2 0. D》 2212402002803 20240200280300 22024020028030 220240260280900 wavelength, nm wavelength, nm Wavelength, nm